Decentered 24-70mm GM ii

coastlight · Jul 29, 2022

As some of you suggested, I did the same test with another lens, the Sigma 35mm f1.2:

ISO100 1/1000s f1.2 35mm

Hard to compare the lenses directly as the chimney is smaller in the frame here, but the point is I can't say I'm seeing anything that resembles the decentering pattern of the 24-70 GM ii

coastlight · Jul 29, 2022

At least it seems the decentering in the upper right corner is pretty much gone when zooming out to 35mm. Actually the lower left corner appears slightly worse here.

Upscaled to 200% for easier viewing:

ISO100 1/400s f2.8 34mm

And just for the direct comparison, here's the 35mm f1.2:

ISO100 1/1000s f1.2 35mm

The Sigma appears really consistent across all corners, at least as good at f1.2 as the GM ii at f2.8

coastlight · Jul 29, 2022

Jeff2013 said:
I agree with a previous poster that is likely lens tilt. I’m sure that it is within factory spec.

I have tested a ton of zooms and yours really is not out of the ordinary, comparatively speaking, I would take a test shot where you focus on the ‘bad’ corner. If this negates any field curvature and you get greater sharpness, then eyes, or any subject matter, placed toward this corner should be sharp.

99% of users would likely be happy with this lens. The problem is that you know about the flaw.

Yes, I have been happy with the lens, used it a lot during the summer. It's versatile and I've got some great pictures with it. It's very good in the centre so portraits etc really pop. Handling is great too. But as I said, I did become suspicious after looking at some landscapes before beginning the tests to confirm the flaw. So it's not just theoretical, it can show up in images. Granted, that corner is usually sky even in landscapes, but not always so.

MILC man · Jul 29, 2022

coastlight said:
Doing some more thorough testing now, will post results later. Can already say that the corner looks pin sharp (at 70mm f2.8) when i put the focus point in that corner. Don't know if I should take that as positive or negative...

you would have had to compare the center to that corner, after focusing in the corner... the center probably would have been soft.

it doesn't matter tho, because there aren't many times you'll be focusing on the corner.

lenses need to be tested at the distance you'll be shooting, across the entire frame, because sometimes there is a mid-field dip that's oof... that dip can be a characteristic of the lens, so the lens isn't actually defective, that's just how it was designed.

4Photos · Jul 29, 2022

Looks like this establishes that you really got a poor copy of the Sony. Too bad the return window is closed which would be the quick fix. Your only option is to send it to Sony to have it fixed. It should still be under warranty.

MattPointZero · Jul 29, 2022

4Photos said:
Looks like this establishes that you really got a poor copy of the Sony. Too bad the return window is closed which would be the quick fix. Your only option is to send it to Sony to have it fixed. It should still be under warranty.

It hasn't been out very long at all - I'd be pushing Sony for a replacement. That's if I could be bothered to return it - it's a tough one for the OP because it isn't an egregious decentering, but it is noticeable, and will now be the first thing they look at! I'd be right on the border of living with it...

MtnView · Jul 29, 2022

4Photos said:
Looks like this establishes that you really got a poor copy of the Sony. Too bad the return window is closed which would be the quick fix. Your only option is to send it to Sony to have it fixed. It should still be under warranty.

Noob here, but they don't look drastically different to me. What do you see that says this is a poor copy of the lens? As the text with the testing instruction states, no lens is perfect and it is all a matter of degree.

Thanks!

JohnNEX · Jul 29, 2022

This test looks fine to me, and I would keep the lens even if I could return it.

JohnNEX · Jul 29, 2022

4Photos said:
Looks like this establishes that you really got a poor copy of the Sony. Too bad the return window is closed which would be the quick fix. Your only option is to send it to Sony to have it fixed. It should still be under warranty.

Your tests establish nothing of the sort. I don't understand how you can conclude that the lens is a poor copy from this test.

There only question from these tests is: do the four corners broadly look the same? The answer to that is yes. Lens is not decentered. Move along.

f1point4andbethere · Jul 29, 2022

coastlight said:
Did the test in line with the method recommended by phillipreeve.net. Here's the result at f2.8:

ISO100 1/250s f2.8 70mm

And at f8:

ISO100 1/125s f8 70mm

All 100% crops, view at original size.

This looks like a normal amount of field curvature to my eyes. Both the opposing corners (in fact, all of your corners) are very slightly focused behind the chimney. If the top right were focused behind but the bottom left focused in front, then you would have tilt issues. I’m not seeing that here though. Keep the lens.

coastlight · Jul 29, 2022

Did quite a lot of tests today, and as the sunlight faded and air cooled I could do more distant subjects on the horizon without hot atmospheric air in the way. I think the bad upper right corner is pretty obvious here:

100% crops:

ISO100 1/2000s f2.8 70mm

By the way, doing tests at different focal lengths is quite confusing with this lens. While by far the worst performance is at 70mm in the upper right corner, at 50mm both the upper and lower right are soft while the left side is sharp (at 70mm lower right is excellent, as you can see). And at 35mm all corners except for the lower left are good. I don't see the logic in such varying performance across the focal range, it'd have expected the upper right to be the worst across the range but clear up a bit as I zoom out. Perhaps someone more knowledgeable can offer an explanation for this...

coastlight · Jul 29, 2022

JohnNEX said:
This test looks fine to me, and I would keep the lens even if I could return it.

I appreciate the advice. The thing is, based on all the reviews that came out at launch, I really expected a close to perfect lens. I seriously considered the Sigma equivalent at half the price, and decided on the GM ii because the Sony name and the reviews inspired confidence. I'd more have expected the Sigma to have a flaw like this, and I feel kind of cheated out of the extra money I paid for the Sony. Sure it won't show up in 95% of photos, and certainly not at Instagram resolutions, but I do print large landscapes sometimes and am a bit of a perfectionist.

101Colors · Jul 29, 2022

@Coastlight, I gotta ask. What was the delay in testing this lens, particularly if you knew there was a return window ?

Or maybe a better q, what caused you to even test the lens ?

coastlight said:
JohnNEX said:

This test looks fine to me, and I would keep the lens even if I could return it.

Click to expand...

I appreciate the advice. The thing is, based on all the reviews that came out at launch, I really expected a close to perfect lens. I seriously considered the Sigma equivalent at half the price, and decided on the GM ii because the Sony name and the reviews inspired confidence. I'd more have expected the Sigma to have a flaw like this, and I feel kind of cheated out of the extra money I paid for the Sony. Sure it won't show up in 95% of photos, and certainly not at Instagram resolutions, but I do print large landscapes sometimes and am a bit of a perfectionist.

coastlight · Jul 29, 2022

MILC man said:
you would have had to compare the center to that corner, after focusing in the corner... the center probably would have been soft.

it doesn't matter tho, because there aren't many times you'll be focusing on the corner.

lenses need to be tested at the distance you'll be shooting, across the entire frame, because sometimes there is a mid-field dip that's oof... that dip can be a characteristic of the lens, so the lens isn't actually defective, that's just how it was designed.

When focusing on the upper right corner at 70mm f2.8 the center is soft and gets sharp way in front of the focus plane...

coastlight · Jul 29, 2022

101Colors said:
@Coastlight, I gotta ask. What was the delay in testing this lens, particularly if you knew there was a return window ?

Or maybe a better q, what caused you to even test the lens ?

I stated earlier that I noticed the softness in some landscapes so decided to test it.

I got the lens in June and there are two main reasons I didn't test it back then: (1) I trusted the GM branding, and (2) I was a bit busy at the time.

I actually assumed Sony wouldn't allow bad copies of their new flagship standard zoom, as it's bad for their reputation. I won't make that mistake again.

I also assumed with GM lenses QC would be very good and sample variation low. It's my first GM lens.

MtnView · Jul 29, 2022

I apologize if this sounds snarky, but it seems like you are going to be unhappy with this lens as long as you have it. You can try to go back to the original seller to see if they'll give you an extension on the return, or sell it on FM and try something else. The next owner may be perfectly happy with the performance.

If you are going to look at every picture with this lens and see softness in the corners, you'll never enjoy it. Eat the couple hundred dollars, move on, and enjoy your next lens.

Jeff2013 · Jul 29, 2022

coastlight said:
JohnNEX said:

This test looks fine to me, and I would keep the lens even if I could return it.

Click to expand...

I appreciate the advice. The thing is, based on all the reviews that came out at launch, I really expected a close to perfect lens. I seriously considered the Sigma equivalent at half the price, and decided on the GM ii because the Sony name and the reviews inspired confidence. I'd more have expected the Sigma to have a flaw like this, and I feel kind of cheated out of the extra money I paid for the Sony. Sure it won't show up in 95% of photos, and certainly not at Instagram resolutions, but I do print large landscapes sometimes and am a bit of a perfectionist.

Over the years, Ive shot a lot of 24-70mm f2.8's - Nikon, Canon Version 2, Sony A-mount Zeiss, GM 24-70mm f2.8 Version I and, finally, the Sigma DG DN lens. The only one I was mostly happy with was the Sigma, although, the Canon VII wasn't too bad. I simply switched to shooting primes for critical work. After testing the stellar and nearly flawless GM 70-200mm f2.8 II, I thought I might take a chance on the new GM 24-70mm II. I think you might have saved me $2,200. I'll just stick with my primes - at least, for now.

As a note, Lloyd over at www.digilloyd.com says he went through three badly de-centered or tilted lenses before he obtained a good copy which he claimed to be really excellent. With those kind of odds, you only have three lenses to go.

--
Jeff
Florida, USA
http://www.gr8photography.com

coastlight · Jul 29, 2022

Jeff2013 said:
Over the years, Ive shot a lot of 24-70mm f2.8's - Nikon, Canon Version 2, Sony A-mount Zeiss, GM 24-70mm f2.8 Version I and, finally, the Sigma DG DN lens. The only one I was mostly happy with was the Sigma, although, the Canon VII wasn't too bad. I simply switched to shooting primes for critical work. After testing the stellar and nearly flawless GM 70-200mm f2.8 II, I thought I might take a chance on the new GM 24-70mm II. I think you might have saved me $2,200. I'll just stick with my primes - at least, for now.

As a note, Lloyd over at www.digilloyd.com says he went through three badly de-centered or tilted lenses before he obtained a good copy which he claimed to be really excellent. With those kind of odds, you only have three lenses to go.

If they really had pride in their product they'd offer a voluntary recall to those who purchased this lens early. I don't think it's a question of whether one "can live with it" or not, the lens is simply too expensive for these variations to be acceptable.

photomad · Jul 29, 2022

Ive had the most problems over the years with centred 24-70's. Its clearly one of the harder zooms to centre correctly.

I currently have a very good Sigma 24-70mm DG DN which took a couple of copies to get a good one. The first one I had was atrocious at 70mm.

Ive been through 2 copies of the new Sony GM now and both were worse then my Sigma. Ive given up going any further with it. The Sigma is a pretty good copy and Ive lost interest in playing the roulette on the GM.

Future investment will be in primes.

4Photos · Jul 29, 2022

JohnNEX said:
4Photos said:

Looks like this establishes that you really got a poor copy of the Sony. Too bad the return window is closed which would be the quick fix. Your only option is to send it to Sony to have it fixed. It should still be under warranty.

Click to expand...

Your tests establish nothing of the sort. I don't understand how you can conclude that the lens is a poor copy from this test.

There only question from these tests is: do the four corners broadly look the same? The answer to that is yes. Lens is not decentered. Move along.

Does this look "broadly the same" to you? Really?

Decentered 24-70mm GM ii

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