SONY AF 85mm f/2.8 SAM

[DonSchap]

So, how about that SONY AF 85mm f/2.8 SAM, huh?

Well ... I thought this lens might be a band-aid for the a850, because it is Full Frame lens... but, sadly... it is all that great.

I conducted a side-by-side test of three similar length lenses:

1) TAMRON SP AF 90mm f/2.8 Di MACRO
2) Rokinon MF 85mm f/1.4
3) SIGMA AF 85mm f/1.4 DG EX HSM

It was worse than any of them... all at f/2.8

Now, I know a lot of folks are going to say, provide some proof. I say, "FINE," be that way.

PROOF (<- click on this and enjoy )

Truth & Knowledge: The bottom line, for the $299 it costs, it is attractive, but for your best photography... I suggest you spend the meager $100 more and get the TAMRON SP AF 90mm f/2.8 Di MACRO, instead. It may be slower to final focus, because of its MACRO capability, but it will deliver a sharpness and a purely accurate focus that is simply unparalleled by even the other two lenses.

Call it a gift of knowledge.

[OsmosisStudios]

2 things

1: f/2.8 is 2 stops down for the two f/1.4 lenses, and the Tamron 90 macro is well-known for super sharpness and is a macro lens designed for the particular testing environment you used. You're compares apples to oranges

2: In your examples, why is the Sony shot larger than the others?

[DonSchap]

Originally Posted by OsmosisStudios

2 things

1: f/2.8 is 2 stops down for the two f/1.4 lenses, and the Tamron 90 macro is well-known for super sharpness and is a macro lens designed for the particular testing environment you used. You're compares apples to oranges

Actually, I was thinking more like bananas. Whatever.

Regardless of stopping the glass down ... focal acuity has to be dead-to-rights. My contention is to have a right proper picture. The SONY is a quick and dirty... not the best idea. If you are financially strapped... and simply have to positively deliver the shot ASAP... well, it is what I have detailed.

Originally Posted by OsmosisStudios

2: In your examples, why is the Sony shot larger than the others?

These shots are what they are. They all have their aspects about them ... and one of those is that they all may not be of equal magnification, due to internal focusing and other such optical oddities. I assure you the distance to subject was nearly identical... and only the lenses were changed to protect the innocent.

[OsmosisStudios]

Originally Posted by DonSchap

Actually, I was thinking more like bananas. Whatever.

Regardless of stopping the glass down ... focal acuity has to be dead-to-rights. My contention is to have a right proper picture. The SONY is a quick and dirty... not the best idea. If you are financially strapped... and simply have to positively deliver the shot ASAP... well, it is what I have detailed.

This is still not a fair comparison. Image quality (or whatever you're meaning by "focal acuity") is something that changes given a lens' aperture range and the selected aperture used in a particular photo. In your example, two of the lenses were a full 2-stops closed down from wide open, while the Sony you're comparing them to is wide open. This is beyond faulty method. Furthermore, you've ignored my comment about the Tamron being a macro lens and thus designed for photos of close-up objects. While you may not have been in the macro range for this particular image, you are still close to the subject, thus favouring the Macro capabilities.

[DonSchap]

Originally Posted by OsmosisStudios

This is beyond faulty method. Furthermore, you've ignored my comment about the Tamron being a macro lens and thus designed for photos of close-up objects. While you may not have been in the macro range for this particular image, you are still close to the subject, thus favouring the Macro capabilities.

My test shots are simply shooting something basically everyone would be able to. Nothing to technically involved ... just set the camera on a tripod, attach the lens, focus and fire away. Replace the lens with a "similar" lens and repeat. Compare the two images ... and it the item under test is... "lacking", you figure out a plan and deal with it.

The TAMRON SP AF 90mm f/2.8 Di lens & the TAMRON SP AF 60mm f/2.8 Di-II LD (IF) are BOTH -> MACRO lenses. Their capability should be so similar that you should NOT be able to tell them apart The SONY Full Frame camera makes allowances for APS-C lenses and as such, the images it delivers, in this case, reveal one lens is performing and the other does not. They are both providing a 90mm focal length image, both actual and effective. What is to be "faulty?"

BUZZ! I sure can when a lens is misfocusing. I expect the 60mm f/2 to deliver a clear, sharp image ... especially being a MACRO. TAMRON has no problem touting this particular lens as the new "be all, end all" MACRO for the APS-C camera market. Well, if that is the case, I am just saying... MAKE IT SO!

My "return-for-adjustment" lens is due back soon, so I will let you know if it got better. If it does not... I will report back on that, too.

Your friend in photography

[OsmosisStudios]

You're still missing the point. If you still cant see it, then I dont know what more I can do to help you. A smack upside the head isnt exactly possible over the internet.

[ravncat]

I`m not sure what kind of field the SONY AF 85mm f/2.8 SAM has, but it`s probably not flat from what I have seen. I think you should try your test again with objects much further away from the camera. Alot of simmilar lenses perform differently at different focal distances. It should be no surprise that the macro lens is doing well here.

Your sony sample certainly is softer than the other samples, but it doesn`t look terrible. What are it`s other characteristics? AF performance, weight, size, flare, color rendition, contrast, abberations, bokeh quality, distortion? Might be that it is better suited for different applications.

[DonSchap]

Keep your hands on your camera, pal. Geesh.

Sitting down and comparing the various lens is a pretty hefty undertaking. You need to keep all the silly variations in mind ... and although closing down aperture would seem to be a no-brainer ... to get equivalent exposure through the lens, admittedly, there are design variations. I suppose that is the point. There are darn few MACRO lenses operating wider than f/2.8. I suppose the reason being that close-up photography has a degree of chromatic aberration when you go wide ... and that is problem. I know I truly appreciate the the dual SD elements in my TAMRON SP AF 180mm f/3.5 Di MACRO LD (IF) and their ability to cancel that part out.

The new TAMRON SP AF 60mm f/2 Di-II MACRO LD (IF) has similar construction and it is rather obvious by the reduced amount of purple fringing I have detected when doing high contrast and highlights. Unfortunately, if you cannot achieve a nice tight focus, who cares?

By doing the 85mm test ... I was able to simply switch from one 85mm (or equivalent) lens and check for the overall response at f/2.8. To be honest, my need for the full aperture of f/1.4 was not the back-breaker at all. I do like the artistic qualities that aperture brings, no doubt, but the price tag is right there, too, unless you give up autofocus (e.g., Rokinon, Vivitar, Boker, Polar, et al <- basically all the same manufacturer {Samyang - South Korea} lenses, different marketing sources).

The Depth of Field for the 85mm @ f/1.4 and 10-feet away is 0.35-feet ... stopping the aperture down to f/2.8 ... it doubles to 0.7-feet. Yes, your entire subject is in focus at that point, not just the face. Is this important? Depends, obviously, for the effect you want. I would say for most beginning photographers, it is not a struggle. Getting a good center focus is probably the harder part.

Now, I'm not exactly sure what the beef is about ... because getting a really decent, flare-free 85mm class lens for a SONY lens can be rather pricey. (I did not include the TAMRON SP AF 60mm f/2 Di-II MACRO LD (IF) because to make use of it, you have to go into SONY a850/a900 "APS-C Capture mode", which changes the resolution of the Full Frame from 24.6MP to an 11MP crop image. You still get an effective 90mm shot, but the physical size (number of pixels) of the image is different and you have to use post-processing to resize to the same proportions of a full frame which unreliably distorts the overall image.)

Rokinon MF 85mm f/1.4 - $269 Camika -Evaluation: Decent image quality, but all manual operation from focus to aperature - no lens contacts - no ADI
SONY AF 85mm f/2.8 SAM - $299 SONY & Retailers - easy to use, image quality seems rather suspect - eight contact lens = ADI
TAMRON SP AF 90mm f/2.8 Di MACRO - $409 (w/rebate) Camera Retailers - very slow to focus due to MACRO gearing, superior image quality - eight contact lens = ADI
Minolta AF 85mm f/1.4 G - typically $800-900 ebay and sourcing elsewhere - Superior Image Quality - five contact lens = no ADI
SIGMA AF 85mm f/1.4 DG EX HSM - $899 Camera Retailers - Excellent image quality, exceptionally quiet focus - eight contact lens = ADI
SONY CZ 85mm f/1.4 - $1369 SONY & Retailers - Superior image quality - eight contact lens = ADI

If you can live with slow focus ... the TAMRON 90mm is a nice choice, but it has some purple fringing issues in high-contrast environments.

[DonSchap]

Originally Posted by ravncat

I`m not sure what kind of field the SONY AF 85mm f/2.8 SAM has, but it`s probably not flat from what I have seen. I think you should try your test again with objects much further away from the camera. Alot of simmilar lenses perform differently at different focal distances. It should be no surprise that the macro lens is doing well here.

Your sony sample certainly is softer than the other samples, but it doesn`t look terrible. What are it`s other characteristics? AF performance, weight, size, flare, color rendition, contrast, abberations, bokeh quality, distortion? Might be that it is better suited for different applications.

The SONY AF 85mm f/2.8 SAM is physically small, in comparison to the other lenses. It has a 55mm-filter size and weight is almost negligible. For a pocket lens, it would be unparalleled at that focal length. If you had only an APS-C camera and carried the SONY DT 35mm f/1.8 SAM, SONY DT 50mm f/1.8 SAM and the SONY AF 85mm f/2.8 SAM as your choices, they would have a combined weight of a 75-300mm f/4-5.6 lens (18 oz). That is some serious indoor light capture. So, there is that and not much out there to compete for the price.

Don't get me wrong about all this. There are merits to every choice. If you can afford it ... collect the bunch. My biggest gripe is simply getting it all in one package for less that $1000. Aperture, speed, stealth, focal clarity, IQ, color. The SIGMA is my choice. It feel it represents, out-of-the-box, the best overall for the least.

[OsmosisStudios]

Still wont admit your testing is flawed, and therefore that your results are = useless thread.