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A900 & APS-C

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Phil Wood View Drop Down
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Post Options Post Options   Quote Phil Wood Quote  Post ReplyReply Direct Link To This Post Topic: A900 & APS-C
    Posted: 09 November 2018 at 23:04
I am a recent convert to FF - doing so on the cheap with an A900. I knew my APS-C lenses would not give FF views and expected the vignetting. What I hadn't realized was that the A900 would not capture this FF vignette.

Two lenses in particular react a little oddly.

My Sony DT 50mm f1.8 automatically triggers the APS-C mode (no surprise there) but the viewfinded image is FF, no obvious vignetting, as far as I can tell pretty sharp in the corners. It's as if a FF lens has been handicapped to stop it taking market share from Sony's far more expensive FF 50mm offerings. Given the number of Min f1.7s out there this seems absurd, but . . .

The other lens is my Sigma 10-20mm f4.5-5.6 - massive vignetting, but the sort of width I cannot get with any other lens- like a 7mm in a 4:1 aspect. As it is not Sony it is not recognised and does not trigger APS mode automatically. Instead I get an error message in the viewfinder 'Lens'. Sadly it will not take a picture until I manually turn the APS-C mode on. Still the widest image I can get, my widest FF lens is 24mm.

Has anyone found a work round to allow the whole frame to be captured using an APS-C lens on an A900?

I had hoped to get some extra wide crops or circular image effects. It's not a big deal, but I do feel that Sony have pointlessly stopped me having as much fun as I could have.
 



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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 09 November 2018 at 23:59
My SIgma 10-20mm f4.5-5.6 worked okay on my A900. I recall it vignetted below 15mm but was fine at 15-20mm through the OVF, but sometimes still clipped the corners on the image depending on the aperture.

Some of the APS_C lenses do work quite well on APS-C if you can disable the auto APS-C mode, eg by slightly unscrewing the bayonet so the contacts don't make. Of course the aperture doesn't work properly then.

I found it rather annoying that when you use a 1.4x TC which optically makes APS-C lenses okay on FF< they're still disabled, but the lens I wanted to use most that way, the Sigma 10-20, gave significantly poorer results that way than on the A58, so I stopped doing it.

You cannot accurately judge vignetting through the viewfinder. Most of them don't give anywhere near 100% view and even though the A900 does, the OVF still doesn't show the same vignetting as the images taken. This is partly because the eye doesn't notice vignetting through an OVF (or evne an EVF) as much as an image on a monitor, but I think there may be something optical going on as well.

I have plenty of Minolta film cameras where an APS-C lens looks absolutely fine through the OVF, and the film images show a big black border on them ...

Edited by Miranda F - 10 November 2018 at 00:03
Miranda F & Sensorex, Sony A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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Phil Wood View Drop Down
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Post Options Post Options   Quote Phil Wood Quote  Post ReplyReply Direct Link To This Post Posted: 19 November 2018 at 11:32
I have resolved one issue - upgrading the A900 to v2.00 firmware (a simple process) adds a 'Release w/o lens' setting - I can now take full frame shots with my Sigma 10-20!

Sony DT lenses still turn on the APS-C crop mode - it would be nice to have another firmware change to allow this to be optional.

The 1.4x TC issue is an irritant, but I am happy enough to use APS-C lenses on APS-C bodies if I want their zoom range - or even use the crop mode on the A900. It is the extra width that I'd like to play with even if it means soft/vignetted corners or letterbox crops.
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pegelli View Drop Down
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Post Options Post Options   Quote pegelli Quote  Post ReplyReply Direct Link To This Post Posted: 19 November 2018 at 21:18
Originally posted by Phil Wood Phil Wood wrote:


Has anyone found a work round to allow the whole frame to be captured using an APS-C lens on an A900?


Slightly clunky and only for wide open aperture (no aperture control), press the lens release button and a Minolta/Sony DT lens will no longer be recognised as DT and the full frame will be captured.

Most 3rd party (eg. Sigma and Tamron) APS-C lenses don't get recognised as such, so will deliver the full frame (with full aperture control) without any workarounds

Edited by pegelli - 19 November 2018 at 21:21
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horizon View Drop Down
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Post Options Post Options   Quote horizon Quote  Post ReplyReply Direct Link To This Post Posted: 19 November 2018 at 23:24
A number of years ago I didnt have a FF WA Lens at the time and I would sometimes use my 16-105 lens from my A700 on my A900. And of course the camera would say that the image was cropped.

However, as I was shooting RAW, in PP (I dont remember if it was an early version of LR or PS) but with one click you could reset all the cropped images back to FF as the whole sensor was working and recording the image.

This could be applied to the all the images using that lens and do a batch UnCrop for the FF image.

This removed the issue of the possibility of the lens dropping off or a lightleak at the flange.

I dont know if the later versions of the PP Software will allow you to disregard any in camera cropping on the RAW files, however, it might be worth a try at least on one frame to know if you can just shoot as normal and correct in post.

Hope it helps.

Regards,
Craig
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Phil Wood View Drop Down
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Post Options Post Options   Quote Phil Wood Quote  Post ReplyReply Direct Link To This Post Posted: 21 November 2018 at 16:00
Originally posted by horizon horizon wrote:

However, as I was shooting RAW, in PP (I dont remember if it was an early version of LR or PS) but with one click you could reset all the cropped images back to FF as the whole sensor was working and recording the image.


Nice idea but I can't see that this can work - the crop mode RAW files are less than half the size of the FF files, they surely can't include the rest of the FF image.

I certainly can't see any option in LR to do it and my PS (CS3) can't read ARW files.
 



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pegelli View Drop Down
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Post Options Post Options   Quote pegelli Quote  Post ReplyReply Direct Link To This Post Posted: 21 November 2018 at 16:36
Originally posted by Phil Wood Phil Wood wrote:

Nice idea but I can't see that this can work - the crop mode RAW files are less than half the size of the FF files , so I find it hard to imagine they include the rest of the FF image.
I can't test it anymore because I sold my A850 (which I assume behaves the same as an A900) But I agree with Phil, all my A850 files in APS-C mode are less than half the size of the FF files (~11 MB APS-C vs. 24 MB FF), and even slightly smaller than my A700 files. So I can't imagine the FF crop is still available in the raw file.

Edited by pegelli - 21 November 2018 at 16:54
Mind the bandwidth of others, don't link pictures larger then 1024 wide or 960 pix high, see here
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horizon View Drop Down
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Post Options Post Options   Quote horizon Quote  Post ReplyReply Direct Link To This Post Posted: 22 November 2018 at 06:07
Sorry, I remembered incorrectly.

I went back through my archives and found that my A900 raw files from the time that I used the 16-105 lens on it and my raw files are 17.8MB.
I then did a bit of testing to find why I thought that I was able to reset the APS-C Raw files back to FF. And what I found was that I did it the other way, I used a FF Lens and told the body to shoot in APS-C Mode and then I could reset the image size back to FF.

I appologise for throwing in a red herring. I hadnt looked at those files since 2010 and was just going from memory, which for me is often not that good.

Regards,
Craig
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SnowFella View Drop Down
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Post Options Post Options   Quote SnowFella Quote  Post ReplyReply Direct Link To This Post Posted: 22 November 2018 at 08:00
Still an interesting "development" in that RAW files shot with a FF lens but in crop mode would retain the full size. Can't say I've ever heard of the feature working that way around.
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Post Options Post Options   Quote horizon Quote  Post ReplyReply Direct Link To This Post Posted: 22 November 2018 at 10:30
I've just reread my previous post, and to save some possible confusion, the RAW files referred to in my above post are from my A900 not from an APS-C body.
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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 22 November 2018 at 10:40
The snag is that with an OVF the crop mode isn't full-screen anyway so it's not of a lot of use!
Miranda F & Sensorex, Sony A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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pegelli View Drop Down
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Post Options Post Options   Quote pegelli Quote  Post ReplyReply Direct Link To This Post Posted: 22 November 2018 at 12:16
Originally posted by Miranda F Miranda F wrote:

The snag is that with an OVF the crop mode isn't full-screen anyway so it's not of a lot of use!
There are black L-shapes indicating the APC-C crop in the A850/A900 viewfinder, so figuring out what's in or out of the frame is straight forward. The disadvantage is that what you actually get in the frame is smaller in the viewfinder. However there is an advantage as well, i.e in shooting sports or other action you see your subject coming before it's actually in the frame. So in fact it is somewhat similar an old rangefinder camera with a larger viewfinder and framelines either printed or projected into your view (like my old Leica M2).
Mind the bandwidth of others, don't link pictures larger then 1024 wide or 960 pix high, see here
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Post Options Post Options   Quote Pirate Quote  Post ReplyReply Direct Link To This Post Posted: 14 February 2019 at 02:20
Ahoy!

Set the camera to APS-C mode as follows:

Setup Menu 4, APS-C Size Capt. On = APS-C & Off = Full Frame

Set your creative style to DEEP if you shoot jpg or both RAW + JPG from this Dyxum thread and you'll see what others reported after they set-up their cameras and you'll see how to do this.

You also need to use the inner rectangle for framing when using APS-C lenses on A850/A900.



There's a very good article about this here.
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Phil Wood View Drop Down
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Post Options Post Options   Quote Phil Wood Quote  Post ReplyReply Direct Link To This Post Posted: 15 February 2019 at 12:57
Originally posted by horizon horizon wrote:

Sorry, I remembered incorrectly.

I went back through my archives and found that my A900 raw files from the time that I used the 16-105 lens on it and my raw files are 17.8MB.
I then did a bit of testing to find why I thought that I was able to reset the APS-C Raw files back to FF. And what I found was that I did it the other way, I used a FF Lens and told the body to shoot in APS-C Mode and then I could reset the image size back to FF.

I appologise for throwing in a red herring. I hadnt looked at those files since 2010 and was just going from memory, which for me is often not that good.

Regards,
Craig


Sorry, I missed this when you posted it.

It is a little worrying if the camera saves FF RAW files when set to APS crop mode under any conditions - I can't imagine using this mode with a FF lens if I wasn't wanting to save storage space?

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