a850 and DT lenses

[Bruce Oudekerk]

I’m still on my ‘honeymoon’ with my new FF a850 and love the camera. My viewfinder issues with the a900 just don’t exist on this camera. Except for the marks it leaves in my nose of course. LOL

My game plan all along was to use my KM28-75D f2.8 indoors and a M28-135 f4-4.5 outdoors and have the SAL70-300G for longer work. I have a tiny M50 f1.7 that I keep in the bottom of my bag for low light whatever. So far this had proven as a nice workable setup of me.

Just yesterday I experimented with the a850 and my APS-C Sony 18-250 ‘just to see’ what would happen and what the IQ would be like. I’m already spoiled by the one-two IQ punch of the old 28-135 and the new G. I was wondering where the 18-250 would actually vignette especially in the wide end. I had contemplated sometime getting an inexpensive 20mm-something for landscapes …maybe… and was pleasantly surprised at what the 18-250 could actually cover down around 18mm. But not as UNPLEASENTLY surprised as I was in realizing that I can NOT defeat the APS crop feature of the a850. I am completely baffled by the Sony rationale. I was told at both the store where I eventually bought the camera AND at PhotoPlus Expo that the APS crop feature could be turned OFF completely and that is apparently incorrect. They had both said that I would be able to shoot and later crop off the objectionable vignette portion. But as far as I can see, this feature can only be overridden and artificially turned ON for full frame lenses…not turned OFF for APS-C lenses. Thus you can sensor-crop the image with a full frame lens via the menu system but can’t turn it off and use an APS-C lens to expose the entire (vignetted) 35mm sensor. That’s a very unpleasant surprise and a bizarre design decision in my estimation. The 18-250 is pretty sharp wide open abet with significant distortion but that is mostly correctable in PP. Especially since I would only be using it on landscapes when cropping it wide and narrow to utilize more of the sensor…I had hoped. For a few moments I actually thought I could use it almost to 20mm or so.

Am I doing something wrong? I sure hope so.

Bruce

[01af]

I was told at both the store where I eventually bought the camera AND at PhotoPlus Expo that the APS crop feature could be turned OFF completely and that is apparently incorrect. They had both said that I would be able to shoot and later crop off the objectionable vignette portion.

Prior to your buying decision, they will tell you whatever you want to hear.

But as far as I can see, this feature can only be overridden and artificially turned ON for full-frame lenses … not turned OFF for APS-C lenses.

Exactly. It's supposed to protect the customers from their own stupidity.

Am I doing something wrong? I sure hope so.

No, unfortunately you don't.

-- Olaf

[Bruce Oudekerk]

> Exactly. It's supposed to protect the customers from their own stupidity.

It would seem to me that having to go into a deep menu item to defeat/turn-off a "feature" would be protection enough. There isn't really ANY justification I can see why this can't be truly turned off for a DT (APS-C coverage) lens considering they obviously went out of their way to design the feature in.

To be honest I can't think of any reason I'd ever turn the APS frame coverage feature ON with a FF lens when I can just crop the image in PP. It’s not as though those tiny APS-C brackets are so easy to use in the viewfinder. Now there’s a feature that could get you in big trouble quickly...shooting in APS mode with a full frame lens and finding out about it later. If they REALLY want to protect me they should ax this feature completely. Or if they really want to protect me, give me a dual-exposure compensation dial on the top of the camera where its 'in-my-face 'what +/- EV I've dialed in from my last photo shoot. I understand that this dual-dial, like on my KM7D, is NOT to everyone’s liking, but I love it. For a menu item the Sony implementation admittedly is elegant.

If I were a cynical person I would say that the only justification to not being able to turn the feature off is to sell more lenses. <SIGH>

But, whatever, this is an irritating feature to me and there should at least be a workaround. I'm stretching my camera system budget as is and if I can 'make do' I should have that ability. In many ways this reminds me of the lack of MLU in the a550. Most users of this level of camera will not use this feature but a few will and it looks good on the feature check list, if for no other reason. IMO this lacking is certainly no deal-breaker, but it enhances the versatility of the camera for some…so why isn’t it there? “Protect me from my own stupidity!”…Sony doesn’t have a chance. LOL

Bruce

[KevinBarrett]

The APS-C crop feature will occur unfailingly for Sony branded DT lenses, but not for similarly specified third-party lenses. Buy the Tamron or KM version over the Sony, and you'll save a few dollars as well as a few headaches.

[Bruce Oudekerk]

The APS-C crop feature will occur unfailingly for Sony branded DT lenses, but not for similarly specified third-party lenses. Buy the Tamron or KM version over the Sony, and you'll save a few dollars as well as a few headaches.

...as in the similar 'Tamron 18-250' would probably NOT automatically force the auto-APS cropping??? This is really bizarre.

Bruce

[David Kilpatrick]

It depends on the lens identity. It is remotely possible that a third party maker could use the identity of a crop format Sony lens for a full-frame design, and end up with a lens which forced a crop when you don't want it EVER. So far that has not happened. What they have done is to use spare identities. I can't answer for the 18-250mm, but I know the Tamron 11-18mm does not crop on the A900, while both the Konica Minolta and Sony versions force the crop. But in all three cases the EXIF data is correctly reported. The Sigma 12-24mm does not crop (nor should it) but the lens identity reported is that of a 28-80mm f/3.5-5.6.

David

[Eiffel]

I don't have a Sony FF camera yet, but what happens to the raw files when using a DT lens? Would this provide a workaround?

[Bruce Oudekerk]

I don't have a Sony FF camera yet, but what happens to the raw files when using a DT lens? Would this provide a workaround?

At least with my Sony 18-250 it’s cropped in RAW as well as JPEG. Going along with that, while I was fiddling around and alternately musing, “What is going on here?’ or “What were they thinking?”, I noticed that the image size in the menu automatically jumps down when the DT/APS-C lens is attached. And the EXIF shows the correct focal lengths of course.

Bruce

[DonSchap]

I don't have a Sony FF camera yet, but what happens to the raw files when using a DT lens? Would this provide a workaround?

At least with my Sony 18-250 it’s cropped in RAW as well as JPEG. Going along with that, while I was fiddling around and alternately musing, “What is going on here?’ or “What were they thinking?”, I noticed that the image size in the menu automatically jumps down when the DT/APS-C lens is attached. And the EXIF shows the correct focal lengths of course.

Bruce

Bruce,

I have both the TAMRON 17-50 & 28-75. The a850 reaction to BOTH lenses is identical and it is NOT tricked into APS-C Capture mode with the 17-50. You get a dandy vignetted image with APS-C Capture set to "OFF". With it on, it adjusts the sensor and delivers a right proper image to the LCD and that dotted frame in the upper right hand corner of the LCD, when you have the display settings on.

So ... I am not sure why the TAMRON 18-250 triggers the internal "DT" switch, but the TAMRON 17-50 certainly does not.

[Bruce Oudekerk]

>>>So ... I am not sure why the TAMRON 18-250 triggers the internal "DT" switch, but the TAMRON 17-50 certainly does not.<<<

Well I'm virtually positive the Sony version ignores the on/off menu and always crops. I can only pre-suppose the Tamron version does not. If so, I find that amazing, amusing and puzzling or something equally astounding. These aftermarket lenses like Tamron and Tokina are supposed to act like OEM branded lenses as they are licensed from Sony…or so I thought. In this case the difference is a plus in my book.

Bruce