Paix et Santé, Pace è Salute pour 2025
La photo a été prise début 2025 sur la commune de Manso 20245 en Corse située à 40minutes en voiture de l'aéroport de Calvi.
Showing posts with label photo. Show all posts
Showing posts with label photo. Show all posts
Thursday, January 16, 2025
Wednesday, November 8, 2017
objectif qui ouvre à 1.2, cas du Minolta Rokkor 58mm f/1.2
Objectif MD (pas AF) nécessite donc une bague d'adaptation.
Rokkor-PG 1:1.2
Minolta MC Rokkor-PG 1:1.2 f=58 mm ou 50mm:Les résultats aux deux tests sont discordants. Au premier il est excellent, à peine dépassé par le grand vainqueur de ce match (MC 50 1,4), par contre au deuxième test il est moyen sans être très mauvais. Il a du se passer un incident lors du 2eme test, peut-être un mauvais réglage de la MAP.
Size: (diameter x length): 70.8mm x 54mm
Filter Thread: 55mm
Weight: 478g
Close Focusing Distance: 0.6m
Number of aperture blades: 8
Price: about 200€
There are 3 mechanically different versions of the lens which share the same optical design:
The first version was built from 1966-1969 and the focusing ring is made completely from metal and flat. It is the rarest of the three versions and its lenses get a yellow cast over time which migh be due to a radioactive element.
The second version was built from 1969-1973 and the focusing ring is also completely from metal but it has some elevations which the first one didn’t have.
The third version is most common and was built from 1973.
The lens has a rubberized waffle style focusing ring and while all the earlier versions were labeled Rokkor-PG (indicating a 5 Groups, 7 lenses design) the PG-affix was dropped during the production of this version.
very good review:
https://phillipreeve.net/blog/minolta-mc-rokkor-58mm-11-2/
Minolta MC Rokkor-PG -1.4
Minolta MC Rokkor-PG 1:1.4 f=50 mm:C'est généralement considéré comme le meilleur objectif standard fabriqué par Minolta. Cela est confirmé par la première série de test ou il est franchement en tête sauf à f=2,8 ou il est dépassé par le MC Rokkor 58mm f=1,2. Par contre dans la série paysage il reprend l'avantage sur cette optique à toutes les ouvertures. Donc mon exemplaire confirme au moins que c'est le meilleur 50mm que je possède.
Minolta MC Rokkor-PF 1:1.7
Minolta MC Rokkor-PF 1:1.7 f=50 mm:Les résultats de cette optique sont plutôt décevants. Je m'attendait à un résultat meilleur pour cette optique tout terrain très bien construite. Il est du même niveau que le 1,7 MD. Ses performances sont plutôt correctes dans la première série, mais très quelconque dans la deuxième. Après inspection détaillée de l'optique, il s'avère qu'elle souffre d'un léger décalage de l'infini, peut-être cela explique ses mauvais résultats dans la série paysage ou la mise au point était plus difficile à faire à cause du manque de contraste et de figures géométriques du sujet. J'en conclu que cet objectif est correct.
Ref
http://www.suaudeau.eu/memo/test/Test_des_Objectifs2.htmlReview
https://jonasraskphotography.com/2013/06/19/minolta-rokkor-md-50mm-f1-2-review/
Friday, July 21, 2017
innovation des smartphone/téléphones à moins de 100euros avec 4G & écran 2K (ou très petit) & android ≥7 (et liste des tel pour MAJ) et... stratégie
Liste des tél qui peuvent être MAJ en 7.0 (été 2017):
http://www.frandroid.com/android/mises-a-jour-android/363539_android-n-liste-terminaux-mis-a-jour
En premier, un smartphone est
- un ordinateur complet avec E/S Wifi et wifi direct (hotspot to share wifi), BT 4 et USB 3, clavier/écran et quelques boutons, avec CPU quadri-coeur, GPU, ≥1 Go de RAM et ≥8 Go de stockage, autres puces électroniques...
- un stockage via SD (mémoire interne extensible) avec compatibilité SDXC (max 256Go), et E/S via connecteur SD
- connecteur(s) carte SIM,
- un téléphone cellulaire multibande,
- un/deux (trois) appareils "photo/video",
- une/plusieurs leds pour flash --> lampe électrique, communication optique/opto-électronique,
- un système d'entrée/sortie sonore (micro, prise jack, Haut-parleur, bouton volume)
on peut donc l'utilise pour faire du controle via une sortie jack analogique par exemple TriggerTrap (pour déclencher un appareil photo ou autre)
https://medium.com/triggertrap-playbook/triggertrap-for-ios-and-android-is-now-open-source-a194350e9cfc - une radio,
- une batterie (amovible) et donc un stockage d'énergie,
- un GPS,
- un gyroscope (capteur pour repérer précisément la position et l'orientation de l'appareil dans l'espace) mesure de vitesse angulaire,
- un g-sensor, (accéléromètre, un capteur de mouvement qui permet de mesurer l'accélération linéaire de votre smartphone),
- un magnétomètre (compas).
https://developer.android.com/index.html
https://en.wikipedia.org/wiki/Rooting_(Android)
Je vais prendre comme exemple quelques sociétés "européennes" (made by or made in??) pour le domaine des smartphones à 100€ (été 2017). On voit qu'il y a convergence technique.
Jelly, un projet Kickstarter
https://www.kickstarter.com/projects/jellyphone/jelly-the-smallest-4g-smartphone
Unihertz is based in Shanghai and our team has over 10 years’ experience in cellphone design and manufacturing. Before creating our own products, we worked with many world-class cellphone brands in the past. After our success with our previous product, we have greatly improved and evolved our concepts and processes. We are excited to use Kickstarter as the launch pad for our best product.
Son écran de 2,45 pouces a une résolution de 240 x 432.
Dimension: 93 x 13 x 43 mm.
Il pèse 60g avec batterie.
Mais pour le reste, il sera à même d’assurer n’importe quelle tâche grâce à son processeur quad-core cadencé à 1,1 GHz, un appareil photo de 8 mégapixels au dos et 2 mégapixels à l’avant, ainsi qu’une batterie de 950 mAh. De quoi tenir 3-5 jours avec un usage normal.
Le Jelly se décline en deux modèles :
79€, une version standard avec 1 Go de RAM et 8 Go de stockage,
95€, une version Pro avec le double (2 Go de RAM, 16 Go de stockage).
From Aug 10th, 2017, the price of Jelly Pro will resume to the retail price of $125 and we don't sell Jelly anymore. The accessories will be the same discounted prices until further update.
Un slot SD permet d’étendre la capacité de stockage, bien sûr.
On y trouve aussi un GPS+ gyro...
Certes, la bande des 700 MHz (B28) n'est pas de la partie, mais celles des 800, 1 800 et 2 600 MHz sont bien là, soit l'essentiel pour profiter de la 4G chez tous les opérateurs du territoire. L'autre bonne nouvelle pour ce produit, c'est la présence, sous la batterie (amovible), de 2 logements pour carte nano SIM en cohabitation avec l'espace pour la carte microSD (voir photo ci-dessus). Pas besoin de choisir — alors que c'est encore trop souvent le cas sur les mobiles double SIM — entre l'extension de stockage ou une seconde carte pour les communications !
$9 to get one extra battery, or add extra $10 for one Armband, or add extra $19 for both.
Le Jelly étant un projet Kickstarter, il faudra le financer… ce qui est déjà très largement le cas.
~11000 contributeurs ont engagé ≥1 200 000 $ pour soutenir ce projet!!!
Le prix d’un appareil (le Jelly standard) est actuellement de 79 $ avec une livraison prévue en août 2017. Trois couleurs sont proposées : blanc, bleu et noir.
http://www.lesnumeriques.com/telephone-portable/jelly-plus-petit-smartphone-4g-monde-en-campagne-kickstarter-n62711.html
http://www.journaldugeek.com/2017/05/06/jelly-un-tout-petit-smartphone-4g-sous-android-nougat/
jelly étanche et anti-choc??
4G (1SIM)+2G(l'autre SIM) for the use of 2 SIM cards. We will keep working on it and hope we can make 4G+4G in Q4 2017...
à tester dès réception.
En outre l'effort est tout relatif pour l'optimisation de l'écran tactile sur la face avant, puisque la dalle n'en occupe que 41 %!
En fait le but est aussi de le relier à un vrai ordi pour avoir du 4G et les fonctions smartphones. L'écran n'est qu'un moyen temporaire de sortie pour le paramètrer et téléphoner/SMS.
Wiko
Wiko a annoncé deux nouveaux mobiles, les Sunny 2 (bof) et Jerry 2 (90€) après le Mobile World Congress de 2017 mais sans 4G.http://www.lesnumeriques.com/telephone-portable/wiko-annonce-deux-nouveaux-mobiles-sunny-2-jerry-2-n65015.html
Contrairement à Archos, son concurrent, Wiko ne conçoit pas ses appareils en France, mais les produits sont importés et commercialisés via la PME Wiko Mobile, basée à Marseille. Ceux-ci utilisent généralement le système d'exploitation Android.
La société Wiko Mobile est fondée en 2011 à Marseille par Laurent Dahan en partenariat avec la société chinoise Tinno dont elle est une filiale à 95 %.
Les smartphones Wiko sont basés sur des composants de la société MediaTek. Cette dernière ne livrerait pas les sources de ses drivers ce qui empêcherait la portabilité de versions alternatives d'Android comme celle de CyanogenMod. Une pétition a été lancée pour demander à MediaTek la publication de ses sources.
https://fr.wikipedia.org/wiki/Wiko
Archos
Créée en 1988, le nom de l'entreprise est l'anagramme de CROHAS, du nom de son créateur, Henri Crohas, actuel président du conseil d'administration.L'entreprise vend principalement dans les années 1990 les lecteurs Overdrive (disque dur et CD), et le Scandoubler pour Commodore Amiga, puis les smartphones à partir de janvier 2014.
Les produits Archos sont principalement vendus en Europe. Fin 2004, l'opérateur de télévision par satellite EchoStar Communications investit 10 millions de dollars dans la société Archos en échange d'une participation de 26 % à terme.
partenariat avec ZTE/Nubia:
http://www.lesnumeriques.com/telephone-portable/archos-diamond-alpha-volonte-haut-gamme-a-349-euros-n63847.html
Il existe bcp de modèle à 100€.
http://www.lesmobiles.com/telephones/mobiles_archos.html
http://www.gsmarena.com/archos-phones-90.php
Quelques innovations comme le Stockage Fusionné Archos
Le Stockage Fusionné Archos est une technologie développée par ARCHOS qui permet d'étendre la mémoire interne de votre appareil grace à une carte micro-SD.Par défaut, la mémoire globale de votre appareil est séparée entre la mémoire interne et la mémoire externe (caractérisée par votre carte micro-SD).
Par exemple, si votre appareil possède une mémoire de base de 8 Go et que vous activez le Stockage Fusionné Archos après avoir inséré une carte micro-SD de 64 Go, le système vous indiquera que vous disposez d'un total de 72 Go
Comment activer le Stockage Fusionné Archos ?
http://faq.archos.com/index.php?action=artikel&cat=17&id=419&artlang=fr
Après le redémarrage, la mémoire de la carte micro-SD aura fusionnée avec votre mémoire interne et vous ne verrez plus apparaitre votre carte depuis un ordinateur ou depuis votre appareil.
A noter que l'option Installer la carte SD dans la partie Stockage des paramètres est toujours visible mais cela n'a aucun effet une fois le Stockage Fusionné Archos activé.
Archos Sense 55DC
On peut trouver l'Archos Sense 55DC (sorti 02/2017) à 110€.L'ARCHOS Sense 55DC intègre deux caméras: 13MP avec autofocus et flash LED + 2MP à l’arrière et 5MP à l’avant. Le double capteur assure une image plus nette avec plus de détails. Il offre un mode très grand angle, la possibilité de modifier la profondeur de champ à postériori ou encore de générer des effets Bokeh.
USB Type-C 3.0
Hardw
CPU : Mediatek MT6737, Quad-Core 1.5GHz
GPU : Mali T720
RAM : 2GB, DDR3
Internal Storage : 16 GB
Expandable Storage : Micro SD card, up to 128GB
écran
Diagonal Size : 5.5 inch
Resolution : 1280 x 720 (HD)
Technology Type : IPS, Full lamination, Curved 2.5D edges
Data Rates : 150Mbps / 50Mbps in 4G
Battery Size : 3000 mAh
lecteur d’empreintes digitales
ARCHOS Apps preinstalled : ARCHOS Video & ARCHOS Files
https://www.archos.com/fr/products/smartphones/sense/archos_sense55dc/index.html#specs
Sense 55s
Téléphones de juin 2017:Sense 55s à 139€
http://labo.fnac.com/actualite/archos-sense-55s-un-prix-canon-pour-le-smartphone-a-ecran-sans-bord/
L'écran est une dalle tactile Full HD en base IPS de 5,5 pouces, soit une définition de 1920 x 1080 px sur une diagonale de 14 cm.
Gigaset
Gigaset Communications est une société allemande spécialisée dans les objets communicants et la téléphonie. Elle a son siège à Düsseldorf et existe en tant que tel depuis le 1er octobre 2005 après la dissolution de Arques Industries. Précédemment il s'agissait de la division téléphonie de Siemens.Très connu dans le domaine des téléphones sans fil pour la maison, elle se lance dans le smartphone.
le GS160 est à 100€.
Ce smartphone arbore donc un écran IPS de 5 pouces affichant une définition HD (1280 x 720 px sur 12,7 cm de diagonale). Derrière s'agite une puce Mediatek MT6737 avec ses quatre cœurs cadencés à 1,3 GHz, un GPU Mali-T720 MP1 et 1 Go de RAM. Côté photo, le module principal pointe à 13 Mpx tandis que le frontal est limité à 5 Mpx. Question connectique sans fil, on retrouve l'habituelle compatibilité 4G, le Bluetooth 4.0 et une puce GPS. Le tout est complété par un lecteur d'empreintes au dos, une prise micro-USB ainsi que deux emplacements SIM et un emplacement microSD pour étendre la mémoire de 16 Go. Enfin, la batterie — amovible ! — pointe à 2500 mAh et tout ce beau monde est animé par Android 6.0 et pas de mise à jour!
http://www.lesnumeriques.com/telephone-portable/gigaset-gs160-p39095/test.html
Wednesday, July 19, 2017
lens and zoom sony minolta (Tamron, SIgma) for A-mount or E-mount (adapt)
beercan; Minolta AF 70-210mm f/4
100-200mm f/4.5
List
https://en.wikipedia.org/wiki/List_of_Minolta_A-mount_lenseshttps://en.wikipedia.org/wiki/List_of_Sony_A-mount_lenses
http://kurtmunger.com/sony_lens_chartid223.html
Examples
many zoom
Minolta AF 70-210mm f/4
The first generation body is made of metal. There is a focus limiter switch to speed up focusing. The lens and the Minolta AF 70-210mm f/4 lens are colloquially known as the "beercan" by Minolta/Sony camera users because their lens shape and size closely match the proportions of a typical aluminum beer can.https://en.wikipedia.org/wiki/Minolta_AF_Zoom_70-210mm_f/4
However, production slowed and then eventually stopped for both the AF and MD versions; its successors, the 70-210mm f/3.5-4.5 and 70-210mm f/4.5-5.6 had none of the qualities of the original and build and image quality decreased...
It remains popular, however, for use on digital single lens reflex cameras using the AF system, such as the Sony α. Although relatively bulky and weighty, the lens is valued for its solid build, sharpness, constant maximum aperture and smooth bokeh effect, though it suffers from more pronounced aberrations than equivalent modern designs. It provides a 1:4 magnification (at minimum focus, an object records at 1/4 its size on film or sensor).
For APS-C users; this is a good lens, and can be had for about the same amount of money as Sony telephoto zoom lenses in this category, but not with a constant F/4 aperture, because Sony doesn't offer one. The Minolta AF 70-210mm F/4 is well built, reasonably sharp at all apertures, and considering the constant F/4 aperture; very inexpensive. The main reason you would buy this lens is the use of F/4 at 210mm.
If you don't need the extra stop, buy the smaller and lighter Sony 75-300mm F/4.5-5.6, or the real diminutive (APS-C only) DT Sony 55-200mm (http://kurtmunger.com/sony_55_200mm_f_4_5_6_reviewid212.html), all for about the same amount of money. Many people in chat rooms claim this is the greatest telephoto zoom lens Minolta ever made, unfortunately, that's not true, it's good, but not that good. Again, if you really need the extra stop for low light shooting, go for it, if not, get the more useful Sony models, which have distance encoding, (used mostly for flash), and are much more portable. See the review of the excellent Minolta AF 100-200mm F/4.5 (constant), which is just as good as the 70-210mm F/4 lens.
Diameter filter
100-200mm F/4.5 -->49mm
70-210mm F/4. -->55mm
Here's the really good news; overall, this lens performs much the same as the Minolta AF 70-210mm F/4, but usually sells for half the cost, and is much smaller and easier to carry around.
http://kurtmunger.com/minolta_af_100_200mm_f_4_5id269.html
For those of you with $900, get the much more useful Sony 70-300mm F/4.5-5.6 G SSM, or the way less expensive Tamron 70-300mm F/4-5.6.
http://kurtmunger.com/minolta__af_70_210mm_f_4__reviewid25.html
Big Beercan
The Minolta 75-300mm F/4.5-5.6The Minolta AF 75-300mm F/4-4.5 is one of the original Minolta AF tele-zooms from the mid-to-late 1980s. It's well built, with a minimum of plastic components, which makes it heavy for its size. Sony has a current lens (Minolta designed) with the same focal length, the Sony 75-300mm F/4.5-5.6, which is much lighter, smaller, and is not built as well. Sony also has a better lens than this, the Sony 70-300mm F/4.5-5.6 SSM G.
Here are the good things about this lens; above average build quality with plenty of metal, and a nice focus limiter switch and focus distance window, it's nice and sharp at F/8 on the long end, near 75mm it's sharp wide open. The corners are almost as sharp as the centers, even with full frame coverage.
Now let's talk about the not-so-good things; both axial and lateral color fringing are very strong towards the long end, especially with full frame coverage, and much of it won't go away by stopping down. Manual focusing is a chore as the ring is at the end of the rather long barrel. There is some zoom creep if the lens is not kept level. This lens is large and heavy, much more so than the less expensive, same focal length Sony model mentioned above.
I can't help but think the Sony 75-300mm F/4.5-5.6 may be about as good as this lens. Both have the same color fringing issues. The Sony is smaller, lighter, has Distance integration, and a price tag of about half what you'd currently pay for the Minolta. I suppose they each have their place, and it all depends on someone's preferences. Personally, I'd stay away from both the above mentioned lenses and get the highly recommended Tamron 70-300mm F/4-5.6 USD for a little more money.
http://kurtmunger.com/75300bigbeercanid59.html
four models:
Minolta AF Zoom 75-300mm f/4.5-5.6 2561-100,[42] 2561-110, 2561-600,[42] 2561-610[29] 25611[2] Zoom 35mm 5-pin[42] 55mm[42] No No No 1985-08[29] Black finish
Minolta AF Zoom 75-300mm f/4.5-5.6 New 2649-110 13? Zoom 35mm 5-pin 55mm No No No 1996 Black finish
Minolta AF Zoom 75-300mm f/4.5-5.6 II 2665-110, 2665-160 13? Zoom 35mm 5-pin 55mm No No No 1999 Black or silver finish
Minolta AF Zoom 75-300mm f/4.5-5.6 (D) 2684-910, 2684-960 29 Zoom 35mm 8-pin 55mm Yes (distance encoder) No No 2001 Black or silver finish; succeeded by Sony SAL-75300
https://en.wikipedia.org/wiki/Minolta_AF_Zoom_75-300mm_f/4.5-5.6#SAL-75300
prices
beercan70-80€
https://www.leboncoin.fr/image_son/1149370544.htm?ca=22_s
https://www.leboncoin.fr/image_son/1147708292.htm?ca=22_s
100-200mm F/4.5
40€
http://www.ebay.fr/itm/Minolta-AF-100-200mm-f4-5-Lens/263007873181?_trksid=p2047675.c100009.m1982&_trkparms=aid%3D777003%26algo%3DDISCL.MBE%26ao%3D1%26asc%3D20140620091512%26meid%3Dae4c64003d54413482fc066b7d9da03c%26pid%3D100009%26rk%3D4%26rkt%3D10%26sd%3D263034079053
---
big beercan; Minolta-AF-Zoom-75-300mm 1:4.5-5.6
http://www.dyxum.com/lenses/Minolta-AF-75-300-F4.5-5.6-D_lens55.html64€
lègère fissure
http://www.ebay.fr/itm/Exc-Minolta-AF-Zoom-75-300mm-1-4-5-5-6-D-Black-100-Sony-et-Minolta/322524145753?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20140620091323%26meid%3D61ff5bffbf0f4ababaa9b14599a73dc2%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D162558888795
ZOOM MINOLTA AF 75-300 / 4,5-5,6 II black
50€
http://www.ebay.fr/itm/ZOOM-MINOLTA-AF-75-300-4-5-5-6-II/263034079049?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20140620091323%26meid%3Deb292e7d69a842389da77c79c116aa57%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D322524145753
55€+14=69€
silver
http://www.ebay.fr/itm/MINOLTA-AF-zoom-75-300-1-4-5-5-6-full-frame-Minolta-SONY-Alpha-excellent-/222550590898?hash=item33d10c85b2:g:8CEAAOSwDrNZRuz0
Sony 75-300mm 1:4,5-5,6 Macro - SAL75300
78€
(200€ sony new)
sigma AF 75-300mm 1:4.5-5.6 (BOF)
http://www.ebay.fr/itm/objectif-zoom-sigma-af-75-300mm-1-4-5-5-6-pour-sony-alpha/182619561023?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20140620091323%26meid%3D61ff5bffbf0f4ababaa9b14599a73dc2%26pid%3D100005%26rk%3D5%26rkt%3D6%26sd%3D162558888795or the APO:
http://www.dyxum.com/reviews/lenses/Sigma-75-300mm-F4.5-5.6-APO-DL_review342.html
Sigma 70-300 mm 4-5.6 DG Macro 58 mm
75€ rebuy
https://www.rebuy.fr/i,3416402/photos-et-cameras/sigma-70-300-mm-4-5-6-dg-macro-58-mm-objectif-adapte-a-sony-minolta-a-type-noir
Tamron SP 70-300 mm 4-5.6 Di USD 62 mm
not the old Tamron Objectif AF 70-300mm F/4-5,6 Di LD IF Macro 1/2225€ rebuy TBE
https://www.rebuy.fr/i,9983805/photos-et-cameras/tamron-sp-70-300-mm-4-5-6-di-usd-62-mm-objectif-adapte-a-sony-minolta-a-type-noir
http://www.tamron.eu/fr/objectifs-photo/sp-af-70-300-f4-56-di-vc-usd/
Tamron 70-200 f2.8
The Tamron SP AF 70-200mm F/2.8 Di LD (IF) macro telephoto zoom lens is made in Japan and features a constant fast aperture of F/2.8 with a typical Tamron build quality, meaning the fit and finish are nice, with a metal mount, but there is plenty of plastic to run your hand over, including the zoom ring, focusing ring, and most of the forward barrel section. It looks like metal is used in the first section from the mount area.This lens was designed for a full frame camera. If you have an APS-C camera, the equivalent capture area will be 105mm-300mm. If you want to know what the ridiculously long name of this lens means, look no further. The "SP" means "super performance," and "AF" means auto focus (duh), Di means it's made for full frame use, "LD" stands for "low dispersion" glass to correct for chromatic aberrations, also known as color fringing, "IF" stands for "internal focus," which means the lens doesn't extend in length when focused, and finally, "Macro" means it can focus quite closely, down to almost a third life size in this case.
The Tamron SP AF70-200mm F/2.8 Di LD (IF) macro lens is a low cost alternative to the more expensive Sony model, also tested here. Is it worth it? It all depends on what's important to you.
Build quality is not great like the Sony, and the slot/screw drive focusing system is slow, but pretty accurate. Unfortunately, there are no focus hold or focus limiter buttons to help out, that's the down side. On the up side, the lens performs very well optically, with relatively low distortion, good control of both axial and lateral color fringing, although color fringing is noticeable along the sides at the short end to about 135mm.
The Tamron 70-200mm F/2.8 is slightly soft wide open at all zoom lengths, although F/2.8 results become more soft as you near 200mm. However, by stopping down to F/4 the centers and mid-sections look quite sharp and are totally usable at all focal lengths. The full frame mid-sections and corners need about an extra stop to sharpen up and match APS-C results in most cases, but that's very predictable and normal. My verdict; good image quality from F/3.5-11, and very good image quality from F/4-8.
Use thoughts; Wedding photography; it should work fine (before the booze), if you're wanting to take pictures at a football game from the cheap seats in daylight or with good stadium lighting, the Tamron 70-200mm F/2.8 will perform well. If you're near the sidelines trying to catch the action close by, or shooting events like high-energy rock concerts, I'd probably go for the more expensive Sony 70-200mm F/2.8 G, which has faster focusing along with a focus limiter and focus hold buttons. Bottom line; the Tamron 70-200mm F/2.8 is well worth the price if you don't need fast focusing.
http://kurtmunger.com/tamron_70_200mm_f_2_8reviewid128.html
Thursday, June 15, 2017
APS-C and full frame conversion and comparison; crop factor, focal length, depth of view, depth of field; Canon, Nikon, Sony.
Advanced Photo System type-C (APS-C) is an image sensor format approximately equivalent in size to the Advanced Photo System "classic" negatives of "25.1×16.7 mm". All APS-C variants are considerably smaller than 35 mm standard film which measures 36×24 mm (Full Frame FF sensor)
Sensor sizes range from 20.7×13.8 mm to 28.7×19.1 mm, but are typically about 22.5×15 mm for Canon for example (crop factor=1.62× ).
For the Sony APS HD CMOS sensor of Alpha series (from alpha 100 to alpha 77 (II)), it's 23.5 x 15.6mm (also for Nikon); sensor surface=366.60mm^2, and Sensor Pixel Area = 15.28µm^2 (for 24.3MPix), and crop factor=1.55×. Then a 35mm (24x36mm)-->"35*1.55=54.25mm".
A crop factor (sometimes referred to as a "focal length multiplier", even though the actual focal length is the same) can be used to calculate the field of view in 35 mm terms from the actual focal length.
Many companies manufacture a range of lenses "optimised" for APS-C sensors. For full frame lenses, the sensor is only in the center.
The full-frame lens is bigger, heavier (than APS lens), and uses a larger filter because it has to cover a larger sensor area.
Moreover they are also some differents designs Sony A-Mount and Sony E-Mount camera .
Shortening the flange focal distance to 18 mm (E-Mount) compared with earlier offerings from Sony which used 44.5 mm (A-mount).
Sony also produces E-mount lenses designated as "FE", which cover the entire full-frame image circle.
optics
basis : the 5 parts
The start is the pinhole camera
No lens, only a pin-hole.
The main problem is the quantity of light due to the fact of the very small surface of the hole.
The second problem is an "infinite" depth of view" (all parts are not blurred).
Then with a lens, we have a large "hole" (diaphragm).
With the aperture, we control the depth of view".
The only problem with FF-->APS-C is the size of the sensor and then the angle of view.
Angle of view from lenses at the same focal length
The angle of view (AOV) describes the angular extent of a given scene that is imaged by a camera (~ also this more general term field of view).
See also
Aperture
The f-number
The f-number f/# of an optical system such as a camera lens is the ratio of 2 lengths, of the system's focal length to the diameter of the entrance pupil (effective aperture).
A 100 mm focal length f/4 lens has an entrance pupil diameter of 25 mm.
The standard f-stop scale which is an approximately geometric sequence of numbers that corresponds to the sequence of the powers of the square root of 2:
f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, f/64,...
f/√2, f/(√2)^2, f/(√2)^3, ... (2.8 is 2.828...)
Then the surface increase of 2 when you change the aperture f-number, for example 2.8->4.
When you change a full frame to an APS-C, the aperture of a lens never changes.... Only the focal length and then the f-number. It lets the same amount of light in no matter what. A 2.8 is a 2.8 ever and ever. If you have a smaller sensor doesn't use the whole image coming in.
Fundamentally, f/# is the ratio of the effective focal length (EFL) of the lens to the effective aperture diameter (DEP).
Diameter of the "first entrance lens" or pupils
Moreover remember that the diameter of the first entrance lens (or single lens "diaphragm-like") is very important for the quantity of light and also for the resolution.
and with some effects:
This figure shows the difference in spot sizes between a lens set at f/2.8 and a lens set at f/8.
As pixels continue to reduce in size, this effect becomes more of an issue and eventually is very difficult to overcome. The Airy Disk, or minimum spot size can be calculated using the f/# and wavelength in μm:
You can see the interest of the dimensionless number f/# .
The lambda is the wavelength of light (blue ~ 0.4µm).
| f/# | Airy Disk Diameter (μm) at a Wavelength of 520nm |
|---|---|
| 1.4 | 1.78 |
| 2 | 2.54 |
| 2.8 | 3.55 |
| 4 | 5.08 |
| 5.6 | 7.11 |
| 8 | 10.15 |
| 11 | 13.96 |
| 16 | 20.30 |
The definition of f/# (see below) is limited in the sense that it is defined at an infinite working distance where the magnification is effectively zero. Most often, the object is located much closer to the lens than an infinite distance away, and f/# is more accurately represented by the working (f/#)w:
In the equation for working f/#, m represents the paraxial magnification (ratio of image to object height) of the objective. Note that as m approaches zero (as the object approaches infinity), the working f/# is equal to the infinite f/#. It is especially important to keep (working f/#w) in mind at smaller working distances. For example, an f/2.8, 25mm focal length lens operating with a magnification of -0.5X will have an effective working f/# of f/4.2. This impacts image quality as well as the lens’s ability to collect light.
f/# and Numerical Aperture (NA)
It can often be easier to talk about overall light throughput in a lens in terms of the cone angle, or the numerical aperture (NA), of a lens.
The numerical aperture of a lens is defined as the sine of the marginal ray angle in image space, and is shown in:
Visual Representation of f/#, both for a Simple Lens (a) and a Real-World System (b)
It is important to remember that f/# and NA are inversely related:
Also we must consider some aberrations for example:
Optical Depth of Field
Optical Depth of Field (DoF) Calculator for Cameras
depth of field (DOF), also called focus range or effective focus range is the distance between the nearest and farthest objects in a scene that appear "acceptably sharp" in an image.
In fact focus is possible at only one distance and at that distance, a point ("subpixel") object will produce a point image.
The diameter of the circle increases with distance from the point of focus; the largest circle that is indistinguishable from a point is known as the circle of confusion.
Doubling the f-number will approximately double the depth of field...
others
An other point is the quality of lenses:
lens transmittances of 60%–90% are typical.
and many many bad effects as tilt, flare...
Macro
You’re admiring your work when you see an insect on the flower which you hadn’t noticed before.You have a macro lens and now you want to fill the photo with that insect.At this point, the APS-C camera might be more helpful because you won’t have to stand as close to the insect to fill the frame. While that might be nice for people who don’t like getting close to critters, being at a greater distance also means you’re less likely to scare the insect. And in macro photography, trying not to frighten off your skittish subjects is a big deal and you’ll welcome the advantage you have from being able to work at a greater distance.But that’s not all.
Because getting enough depth of field is notoriously difficult in macro photography, you’ll probably also appreciate the slight increase in depth of field that comes from photographing your insect at the greater distance.
http://www.mdavid.com.au/photography/apscversusfullframe.shtml
Depth of field increases as you move further away from your subject.
This can give an APS-C camera an advantage when taking macro photos
because they fill the frame with your subject from a greater distance.
Note that this graphic is not drawn precisely to scale.
Monday, June 12, 2017
future of the Sony (Minolta) A-mount? dead or not? And Adaptators A-Mount to E-mount. GPS built-in?
The A-mount is no longer seen as a viable platform by Sony executives, because it now represents a small % of all interchangeable camera lens sales.
2016:
http://www.mirrorlessrumors.com/2016-companies-market-shares-japan/
2015:
http://www.diyphotography.net/japan-has-spoken-canon-dominates-sony-dethrones-olympus-and-nikon-stutters/
http://www.sonyalpharumors.com/sony-a68-and-a-mount-in-general-will-no-more-be-sold-in-taiwan/
So after Australia and New Zealand also Taiwan will likely no more sell any A-mount stuff.
I guess Soy’s startegy now is to sell their new A-mount cameras only in “DSLR-friendly” markets.
2017 may
https://www.dpreview.com/news/6936602216/sony-still-third-globally-but-bullish-about-2017
Sony is the world's leading mirrorless camera brand but remains third for ILCs overall, it said in a presentation to investors (imaging product https://www.sony.net/SonyInfo/IR/calendar/presen/irday/irday2017/IPS_E.pdf).
But
https://photorumors.com/2016/03/03/sony-still-comitted-to-the-a-mount/
Lists of all products
https://en.wikipedia.org/wiki/Minolta_A-mount_system
https://en.wikipedia.org/wiki/List_of_Sony_A-mount_lenses
The last A-mount zooms (2015-04)
Sony α Zeiss Vario-Sonnar T* 24-70mm f/2.8 ZA SSM II
Sony α 70-300mm f/4.5-5.6 G SSM II
Example of oldies : https://en.wikipedia.org/wiki/Minolta_AF_Macro_100mm_f/2.8
In french https://fr.wikipedia.org/wiki/Sony_Alpha
for a sheet of all alpha A-mount:
https://en.wikipedia.org/wiki/Sony_%CE%B1330
https://en.wikipedia.org/wiki/List_of_Sony_E-mount_cameras
https://en.wikipedia.org/wiki/List_of_Sony_E-mount_lenses
https://en.wikipedia.org/wiki/Sony_E-mount
Now (june 2017), only 3 Sony A-Mount cameras:
- Alpha 99 II (It was first announced by Sony on September 19, 2016 at photokina 2016 )
(capteur BSI CMOS de 42 Mpx full frame stabilisé sur 5 axes, son processeur Bionz X associé à un co-processeur et son système 4D AF à 399 collimateurs)
http://www.techradar.com/reviews/sony-alpha-a99-ii
https://www.dpreview.com/reviews/sony-slt-a99-ii/9
and still alpha 99 - Alpha 77 II (2014-05);
- Price: 950€ alone (France, FNAC);
- second hand 720€ (France; priceminister); 650€
https://www.rebuy.fr/i,9989040/photos-et-cameras/sony-ilca-alpha-77-ii-slr-digitale-camera-noir - Alpha 68 (2016-04)
- https://en.wikipedia.org/wiki/Sony_Alpha_68
"near" of the A77 II - Price 519€ (amazon; photo-univers) or 517.42€ (pixmania; photo-univers); 509€ (with SDHC 32Gb UHS1 class10)...
- second hand 369€ (price minister; nu)
- Alpha 58 (2013-04) in fact you cannot buy (in France)
- https://en.wikipedia.org/wiki/Sony_Alpha_58
- Price 250€ with the Sony DT SAM 18 - 55 mm f/3.5 - 5.6 (France, FNAC; indisponible)
http://www.fnac.com/Sony-Alpha-SLT-A58-Obj-Sony-DT-SAM-18-55-mm-f-3-5-5-6/a5844850/w-4?omnsearchpos=1; - Second hand 215€ (ebay)
225€: https://www.rebuy.fr/i,9967992/photos-et-cameras/sony-slt-a-58k-noir
Comparison Alpha68 and 58:
http://cameradecision.com/compare/Sony-SLT-A58-vs-Sony-SLT-A68
Reasons to choose Sony SLT-A57 (2012-04) over Sony SLT-A58 (2013-04)
Reasons to choose Sony SLT-A58 over Sony SLT-A574 advantages
Max Sensor Resolution 20 MP vs 16 MP --> 25% more pixels
Battery Life 690 shotsvs 550 shots --> 140 more frames with a single charge
Weight 492 g vs 618 g -->126 g lighter
Reasons to choose Sony SLT-A57 over Sony SLT-A58
6 advantages
LCD Screen Size 3″vs 2.7″ --> 0.3 inches larger display
LCD Screen Resolution 921k dots vs 460k dots --> 100% higher resolution screen
Continuous Shooting 12.0fps vs 8.0fps --> 4 fps faster
Color Depth 23.4 vs 23.3 --> higher color depth
Dynamic Range 13.0 vs 12.5 --> higher dynamic range
Low Light ISO 785 vs 753 --> better High ISO performance?
A57 is better than A58
In french: http://www.lesnumeriques.com/appareil-photo-numerique/sony-alpha-58-p15629/test.html
More
https://en.wikipedia.org/wiki/Sony_Alpha_57http://cameradecision.com/compare/Sony-SLT-A58-vs-Sony-SLT-A57
Alpha 55
200€ https://www.rebuy.fr/i,7673396/photos-et-cameras/sony-alpha-55-noir
(GPS built-in).
- Slow (50 seconds) buffer clear time (RAW-mode)
- Little control over high ISO noise reduction in JPEG mode ('auto' or 'weak')
- Visible loss of detail at anything over ISO 400 in JPEG mode (noise reduction too strong --> blur)
Reasons to choose Sony SLT-A68 (2016-03) over Sony SLT-A65 (2011-03)
Flash Coverage 12.0mvs 10.0m--> 2m longer range
Color Depth 24.1vs 23.4--> higher color depth
Dynamic Range 13.5vs 12.6--> higher dynamic range
Top LCD Yes vs No--> Help viewing and changing settings easily
Smartphone_remote control Yes vs No--> Remote control your camera with a smartphone
AF Micro Adjustment (Fine Tune) Yes vs No--> Adjust each lens for more accurate focusing
http://www.the-digital-picture.com/Photography-Tips/af-microadjustment-tips.aspx
Reasons to choose Sony SLT-A65 over Sony SLT-A68
5 advantagesGPS BuiltIn vs None track your location
LCD Screen Size 3″vs 2.7″ 0.3 inches larger display
LCD Screen Resolution 921k dots vs 461k dots 99% higher resolution screen
Continuous Shooting 10.0fps vs 8.0fps 2 fps faster
Viewfinder Resolution 2359k dot vs 1440k dot 63% higher resolution
A68 plastic mount!!!
http://cameradecision.com/compare/Sony-SLT-A68-vs-Sony-SLT-A65
Moreover the alpha 65 is very near of the alpha 77 (I):
- Comparatively strong noise reduction at medium and high ISO settings
- Very noisy raw files at high ISO settings
- Little control over high ISO noise reduction in JPEG mode ('auto' or 'weak')
- Limited control in 10 fps continuous shooting and movie modes
- No live view in 8 or 10 fps continuous shooting modes makes accurate panning very difficult
- Slightly 'laggy' menu system and UI
Converting the A65 images in Adobe Camera RAW 6.6 Beta confirms the suspicion that we had when examining the camera's JPEG output. The A65's 24MP sensor is producing significantly higher noise levels than the competition, especially towards the top of its ISO sensitivity range. At ISO 1600/3200 and above the disparity is obvious, and becomes more so as the ISO sensitivity increases.
https://www.dpreview.com/reviews/sonyslta65/20
Then bad for low light shooters!
Idem for A77
https://www.dpreview.com/reviews/sonyslta77/
Alpha 77
Jpeg are bad after 3200 ISO.
review in french:
Alpha 99 (2013-04)
https://en.wikipedia.org/wiki/Sony_Alpha_99https://fr.wikipedia.org/wiki/Sony_Alpha_99
SLT-A99V with GPS.
SLT-A99 without GPS (depending on country).
Absence de sortie USB 3, Absence de Wi-Fi ; pas de flash intégré...
c'était le nouveau reflex à capteur 24x36 mm (full frame) de Sony 24 Mpx (loin du 36 Mpx du D800). Corollaire : la densité de pixels reste sous les 3 Mpx/cm², ce qui laisse présager une excellente gestion de la sensibilité.
Two Adaptators A-Mount -->E-mount ; here only model LAEA3
The adapter is good quality, fits tightly to the body and the lens, and when attached you don't notice it at all. The only issue is the auto focus speed.
It's not slow, it's ridiculously slow.
Avec un objectif sur lequel on ne peut pas régler le diaphragme mécaniquement, cet adaptateur est inutilisable car il n'y a pas de communication avec le boitier qui affiche F-- de ce fait le diaphragme reste fermé au maximum (F22) et on ne peut pas faire de photo en manuel.
E-Mount
Shortening the flange focal distance to 18 mm compared with earlier offerings from Sony which used 44.5 mm.
the flange focal distance (FFD):
GPS built-in
Why GPS in cameras is going away?https://www.dpreview.com/forums/thread/3866556
super slow motion, stacking and image sensor; shoot 1000fps at 1080p; detection and tracking of objects at 1000fps
Feb and May 2017
Sony Announces 1000fps (640*470-4bits) Sensor Stacked on Top of Vision Processor
http://image-sensors-world.blogspot.fr/2017/05/sony-announces-1000fps-sensor-stacked.html
Sony announces the IMX382 high-speed vision sensor, which enables detection and tracking of objects at 1,000 fps. Sony begins sampling it in October 2017.
---
Sony shows off 3-layer stacked smartphone image sensor that can shoot 1000fps at 1080p and 60fps 4K.
https://www.dpreview.com/news/5696183465/sony-shows-off-3-layer-stacked-smartphone-sensor-that-can-shoot-1000-fps-at-1080p
http://image-sensors-world.blogspot.fr/2017/02/sony-presents-3-layer-stacked-sensor.html
The new 20MP 1/2.3-inch sensor minimizes the rolling shutter distortions by providing a 8.33ms-fast readout of the full 20MP of the sensor into the internal 1Gb DRAM.
Sample
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