No I meant still put the object in each corner, but it's not vital to rotate it if you don't want to. It might be worth corner focusing as well as centre focusing, although my 12-24 doesn't have bad field curvature. My 14mm GM is awful in the corners if I run this test with centre focusing, but it's okay ish with corner focusing (field curvature is often not uniform/symmetrical). So for corner focusing I'd stick the object in a corner, focus there, then keep that focus & put the object in the other corners.
chrisd999 wrote:
I'm looking to buy a "brand new in box" 12-24GM at a decent discount from a local seller later today. If it is as good as I hope, it will replace my Laowa 12mm, and 16-35GM. But after reading this thread I'm nervous as hell that I'll be stuck with a decentered or soft copy that I can't return.
As this is an in-person meet-up, the seller will give me 15 minutes max to inspect and test it on my A7RIV before buying it. I've seen Fred's decentering test, but given that I'll be in person with the seller, I'm not sure I'm comfortable inverting the camera handheld with his BNIB lens mounted, so I'll probably pick a distant subject and compare the 4 corners at f2.8 normally, then chimping on the LCD or EVF.
Any other quick and dirty tests that you folks would recommend?
I'd be suspicious of any seller that puts a time limit on you...sounds like they might have something to hide. It takes hours of work to properly evaluate a new lens, especially a zoom lens, where four corner infinity tests are not enough to pick up all the wierd things that can go on with zooms: you need a range of 3D deep-DOF scenes for that.
I just picked up a used copy of the 12-24mm 2.8 GM from BH. When the lens is off the camera, if I flip it upside down then rightside up, there's an audible sort of click or movement noise. I usually only detect this noise on lenses with IS as there's a floating optic inside that moves around for IS when on, but sort of floats when off and wiggles around a bit. I don't think I've ever noticed such a noise with a non-IS optic like the 12-24mm before. It doesn't seem to exhibit this noise when mounted on the body (Sony A1) when powered on. I'm assuming maybe this is some focus group/linear focus motors in the middle of the lens floating back and forth when powered off. But, it's a somewhat disconcerting noise, so I wanted to check with forum members here and make sure that this is normal for this lens?
That is normal behavior for many of the latest Sony lenses. I have the Sony 12-24 f/2.8 GM and it makes that sound when turning it upside down then right side up when not attached to the camera and powered on. It is common in a lot of the Sony lenses but seems to sound a bit more prominently on the wider lenses, I hear it almost as loud in my 14 GM and less so but somewhat in my 24 GM , 35 GM, and a bit more loudly with my 50 GM. Also slightly less loud on my 24-70 GM II and 70-200 GM II zooms. There are floating elements in the lenses that shift up and down when the lens is not attached to a camera and powered on.
Chuck Coyne wrote:
That is normal behavior for many of the latest Sony lenses. I have the Sony 12-24 f/2.8 GM and it makes that sound when turning it upside down then right side up when not attached to the camera and powered on. It is common in a lot of the Sony lenses but seems to sound a bit more prominently on the wider lenses, I hear it almost as loud in my 14 GM and less so but somewhat in my 24 GM , 35 GM, and a bit more loudly with my 50 GM. Also slightly less loud on my 24-70 GM II and 70-200 GM II zooms. There are floating elements in the lenses that shift up and down when the lens is not attached to a camera and powered on. ...Show more →
Copy that, thank you Chuck. Helps give me some peace of mind.
One other question for you. I notice that on my A1, the 12-24mm's AF/MF switch on the lens itself does not seem to change from AF to MF on the A1. The focus hold button also doesn't seem to do anything. I have to actually switch the A1 from AF to MF on the selection ring on the body. I just tested with a Sigma 14-24 and my 24-105, neither of them have this issue. On those two lenses, if I flip the switch from AF to MF, it automatically goes to MF on the camera body, and the focus hold button on the 24-105mm works as well. Could this be a faulty lens? Any insight is welcome and appreciated.
One other question for you. I notice that on my A1, the 12-24mm's AF/MF switch on the lens itself does not seem to change from AF to MF on the A1. The focus hold button also doesn't seem to do anything. I have to actually switch the A1 from AF to MF on the selection ring on the body. I just tested with a Sigma 14-24 and my 24-105, neither of them have this issue. On those two lenses, if I flip the switch from AF to MF, it automatically goes to MF on the camera body, and the focus hold button on the 24-105mm works as well. Could this be a faulty lens? Any insight is welcome and appreciated.
That does sound like a problem. My 12-24 GM will switch to Manual focus with the AF/MF switch on the lens barrel no matter what focus mode is selected on the camera's top mode dial. The Focus Hold button also works on the lens as well. Not sure if there is something wrong with the camera settings or the lens itself but it sounds like this could be your lens.
Chuck Coyne wrote:
That does sound like a problem. My 12-24 GM will switch to Manual focus with the AF/MF switch on the lens barrel no matter what focus mode is selected on the camera's top mode dial. The Focus Hold button also works on the lens as well. Not sure if there is something wrong with the camera settings or the lens itself but it sounds like this could be your lens.
Yeah, tried it on another body, same issue. Checked custom buttons, no dice. I guess back to BH it goes. Shame, it was a pretty well centered copied.
TimWildAstro wrote:
After some more nights out and a bit of pixel peeping, the Sigma 14-24 DG DN is better at 14mm for astro than the Sony is in the 12-14mm range (with my copies at least). Taken with an A7Riv and viewed at 50%, both look superb. Zoom to 100% and the Sony exhibits slight stretching on stars midframe if corner focused, and stretching in the corners if focused for midframe. With my Sigma at perfect focus, pretty much all stars are round corner to corner at 14mm (focus accuracy is absolutely critical though, but the Sigma is easier than the Sony there too).
The above is mainly relevant if you're using a tracker though; if you're doing untracked images with slight trailing, then the tighter stars from the Sigma are no longer as beneficial. At 14mm, the Sony has slightly less vignette, and seems to have very slightly better light transmission. For tracked astro, the Sigma is slightly better than the Sony at the wide end....Show more →
With the optimal copies I tested, the Sigma 14-24 does perform slightly better at 14mm wide open, so I don't blame you from preferring it for astro.
Still pleased with the 12-24 GM, especially when I need 12mm. I do now have 2 of the 14mm GM though, decent at f1.8 and essentially perfect corner to corner at f2 at A7iv res, and f2.2-2.5 at A7Riv res.
TimWildAstro wrote:
Interestingly the red colour ring issue is worse with the shading correction turned off with the 12-24GM. I've always used all corrections off for astro, with all lenses, but something is seemingly baked into the files with the 12-24GM regardless of corrections on vs off
This is an old post but I just came across it and checked the files. Are you sure it's not Adobe messing up your files? I couldn't recreate the rings in Rawtherapee (http://rawtherapee.com)
A lot of comparisons, reviews and fault finding online relies on Adobe not messing with the files or doing hidden stuff behind the scenes. Thing is that Adobe does. So much so that you can't really evaluate a lens or camera using it.
Nushi wrote:
This is an old post but I just came across it and checked the files. Are you sure it's not Adobe messing up your files? I couldn't recreate the rings in Rawtherapee (http://rawtherapee.com)
A lot of comparisons, reviews and fault finding online relies on Adobe not messing with the files or doing hidden stuff behind the scenes. Thing is that Adobe does. So much so that you can't really evaluate a lens or camera using it.
It's consistent across various raw processing programs unfortunately. Only certain bodies do it, and apparently covering contacts stops it (I'm not trying that personally) which implies it's irreversibly baked in electronically.
but completely agree with this review by our own BastianK: