Dave Sanders wrote:
If it's like the 45/2.8, it may be dependent on distance to subject. Under 1.5m or so, the 45 is more 'gentle' in its rendering, getting quite glowy as one approaches MFD. Beyond 1.5-3m, the 45 is very, very sharp, edge to edge and corner to corner. I think we need someone like Fred to give the 90 a real once over to see if it follows the same design philosophy.
The softness definitely goes away with increasing focus distance (I guess around ~2m).
Here is an example at F2.8, focus distance was between 3 and 5m:
Yesterday I went to visit Jindai Botanical Gardens and Jindaiji Temple and other areas in Chofu with my Sony A7C and Sigma 90/2.8 DG DN. Some shots, all between f2.8 and f4 (including some PP done in C1 Pro):
jhinkey wrote:
Just got back from taking some quick hand held comparison shots between the 90/2.8Sig and:
- 85/4ZM
- 90/3.5 CV
- 85/1.8G
I can say that the manual focus experience is mediocre. Build quality is great, but you turn the focus ring forever and very little happens. I suppose that might be good as once you get the focus, minor bumps to the focus ring won't change anything. The focus distance scale in the viewfinder with this lens, as with many lenses, is useless.
Quick full image/center/right/left wide open manually focused.
First glance they are not bad. Haven't checked the corners. Time for dinner.
I must have messed up the focus for the f/4 and f/5.6 shots that followed the f/2.8 shots I showed above as they are less sharp. I re-focused between aperture settings to make sure there was no focus shift going on as the aperture was stopped down.
I must say that I find this lens difficult to accurately manually focus because you turn the ring a lot and hardly anything happens, thus you'll turn it to get to critical focus and then you turn it too much because nothing is happening it seems or at least focus is changing very very slowly.
Also, when in AF mode on my A7RIII at least when you turn the focus ring it doesn't cause the camera to jump into fine AF mode with the + in the middle of the magnified view. Seems this lens will need some firmware updates. I haven't tried it yet with my A7C.
Quick one from the walk back home last night.
I was lazy and used AF on the first light and the focus appeared to be fine.
The focus isn't the absolute quickest, but more than good enough for my purposes.
I will try to get out today for better test shots, but the weather kind of sucks right now.
jhinkey wrote:
I must have messed up the focus for the f/4 and f/5.6 shots that followed the f/2.8 shots I showed above as they are less sharp. I re-focused between aperture settings to make sure there was no focus shift going on as the aperture was stopped down.
I must say that I find this lens difficult to accurately manually focus because you turn the ring a lot and hardly anything happens, thus you'll turn it to get to critical focus and then you turn it too much because nothing is happening it seems or at least focus is changing very very slowly.
Also, when in AF mode on my A7RIII at least when you turn the focus ring it doesn't cause the camera to jump into fine AF mode with the + in the middle of the magnified view. Seems this lens will need some firmware updates. I haven't tried it yet with my A7C....Show more →
If the MF focus system is similar to the other Sigma I series, focus throw is very large at around 270 degrees. It's great to focus on fine detail but it takes a lot of rotating. It feels linear but focus throw also varies depending on ring rotation speed.
Interestingly it seems that focus throw and other MF settings can be tweaked with the Sigma USB HUB but it's only available for the L-mount. (Not E-mount).
heisven wrote:
These look good. May I ask how you post-process your pictures?
Thanks! I used latest version of C1 Pro 21 and their Beyond Film Styles on these, K100 I, II or III depending on each photo. The K100 and K200 Styles are inspired by Kodak film stocks. Although these styles come with "film grain" add-on options I didn't add any grain and I have turned all noise reduction settings off on my C1 Pro. https://www.captureone.com/en/products-plans/styles/beyond-film-styles
Additionally I tweaked exposure and brought down highlights on some shots and I tweaked white balance on one of them.
How is distortion with the 90/2.8i? High pincushion distortion is what stops me from getting the 85/1.4 DG DN.
Also, the 90/2.8 is capable of almost twice the magnification of the 85/1.4. (0.2x vs 0.12x)
jhinkey wrote:
I must have messed up the focus for the f/4 and f/5.6 shots that followed the f/2.8 shots I showed above as they are less sharp. I re-focused between aperture settings to make sure there was no focus shift going on as the aperture was stopped down.
I must say that I find this lens difficult to accurately manually focus because you turn the ring a lot and hardly anything happens, thus you'll turn it to get to critical focus and then you turn it too much because nothing is happening it seems or at least focus is changing very very slowly.
Also, when in AF mode on my A7RIII at least when you turn the focus ring it doesn't cause the camera to jump into fine AF mode with the + in the middle of the magnified view. Seems this lens will need some firmware updates. I haven't tried it yet with my A7C....Show more →
I also feel that the focus throw for MF is too long especially when the ring is turned at a slow speed and it's hard to pick the ideal focus point that way since focus doesn't visibly change much at all when turning the ring several degrees. Therefore I've been using my lens primarily with AF only. The feel of the focus ring is otherwise very nice but a shorter MF throw would be welcome for my use.
I don't have auto-magnification (when turning the focus ring) enabled on my cameras as I don't like that being triggered always when turning the ring, but AF mode in magnified view with the + marker works fine with this lens on my A7C when I trigger that mode (just need to have the setting for AF in magnified view enabled). I've used the AF in magnified view option with this lens quite much when shooting close-ups of flowers as it's a very accurate focusing mode for focusing on tiniest details.
Fred Miranda wrote:
How is distortion with the 90/2.8i? High pincushion distortion is what stops me from getting the 85/1.4 DG DN.
Also, the 90/2.8 is capable of almost twice the magnification of the 85/1.4. (0.2x vs 0.12x)
I've not paid attention to the distortion so far as I keep the distortion correction setting at Auto in-camera (for JPEGs) and when I process the raw files in C1 Pro the same distortion correction gets applied automatically via Manufacturer Profile that is applied for the lens (utilizing distortion correction profile from EXIF data). I'll try to check how noticeable the distortion is if I turn the correction off in C1 Pro later today.
Fred Miranda wrote:
If the MF focus system is similar to the other Sigma I series, focus throw is very large at around 270 degrees. It's great to focus on fine detail but it takes a lot of rotating. It feels linear but focus throw also varies depending on ring rotation speed.
Interestingly it seems that focus throw and other MF settings can be tweaked with the Sigma USB HUB but it's only available for the L-mount. (Not E-mount).
I tried the MF focus thrown with my 90/2.8i on Sony A7C and the focus throw is around 270 degrees if I turn the focus ring fast. But if I turn the ring slowly (like I normally would when I'm trying to fine-tune optimal focus), focus throw is much longer. It's hard to measure accurately but it's more than 720 degrees. If it was consistently 270 degrees regardless of the speed of turning the focus ring I think it would be much better...
Would be nice if there was a way to tweak the behavior for the E-mount versions of the lenses as well.
Fred Miranda wrote:
How is distortion with the 90/2.8i? High pincushion distortion is what stops me from getting the 85/1.4 DG DN.
Also, the 90/2.8 is capable of almost twice the magnification of the 85/1.4. (0.2x vs 0.12x)
What was your concern with the 85s distortion? My sense is that it is designed with resolution to “spare” so that after distortion correction it’s still super high rez. Obviously some lenses are at a threshold so they are very sharp before correction but not after, but my sense of the art 85 is that that isn’t a problem. (By sense I mean what I see with my copy without having done careful tests, not having reviewed it)
DavidBM wrote:
What was your concern with the 85s distortion? My sense is that it is designed with resolution to “spare” so that after distortion correction it’s still super high rez. Obviously some lenses are at a threshold so they are very sharp before correction but not after, but my sense of the art 85 is that that isn’t a problem. (By sense I mean what I see with my copy without having done careful tests, not having reviewed it)
The 85/1.4 DN DG's pincushion is not mild and although resolution is still great after correction there is always a MTF reduction.
Personally I prefer lenses with low distortion even if the compromise is slightly bigger size.
I have never seen the distortion in 85/1.4 DG DN. Not in viewfinder, previews, not on my PC. Never anywhere. I use Panasonic S1 and Lightroom Classic. I understand why Sigma opted to not correct it. The 85mm is the sharpest looking lens I own, with smoothest bokeh.
I understand the 24/2 has also tons of optical distortion but it works the same as 85/1.4 DGDN. I never see it and the 24/2 is the sharpest 24mm lens I've ever seen.
Both have quite unusable mf ring due to the slow speed. I'll buy UD-11 dock and see if I can shorten the MF throw to 1/3-1/5 of the stock setting.
Ihmemies2 wrote:
I have never seen the distortion in 85/1.4 DG DN. Not in viewfinder, previews, not on my PC. Never anywhere. I use Panasonic S1 and Lightroom Classic. I understand why Sigma opted to not correct it. The 85mm is the sharpest looking lens I own, with smoothest bokeh.
I understand the 24/2 has also tons of optical distortion but it works the same as 85/1.4 DGDN. I never see it and the 24/2 is the sharpest 24mm lens I've ever seen.
Both have quite unusable mf ring due to the slow speed. I'll buy UD-11 dock and see if I can shorten the MF throw to 1/3-1/5 of the stock setting....Show more →
Well, you either shoot with correction/correct distortion in post or never shot any straight lines .
I might be the biggest 85DN fanboy around here, but its distortion is massive.
Not that it matters to me in the end, as in real life shots I can barely see (50 MP viewed at 100%) any difference in sharpness after correction...
Fred Miranda wrote:
The 85/1.4 DN DG's pincushion is not mild and although resolution is still great after correction there is always a MTF reduction.
Personally I prefer lenses with low distortion even if the compromise is slightly bigger size.
Sure there is a reduction in resolution from before it was corrected; but I’m not sure there is a reduction compared to how it would be if it was optically corrected and the same size (because optical correction also can reduce MTF)
But sure if you are prepared to have larger size you can probably have optical correction and have resolution as high as the smaller sized one pre-correction. That goes both ways with software correction….when LaCA is corrected, the post correction chart improves!
I think it’d be great if manufacturers have us both pre and post correction MTF charts.
DavidBM wrote:
Sure there is a reduction in resolution from before it was corrected; but I’m not sure there is a reduction compared to how it would be if it was optically corrected and the same size (because optical correction also can reduce MTF)
But sure if you are prepared to have larger size you can probably have optical correction and have resolution as high as the smaller sized one pre-correction. That goes both ways with software correction….when LaCA is corrected, the post correction chart improves!
I think it’d be great if manufacturers have us both pre and post correction MTF charts.
Can anyone provide an example of an image that was harmed in its visual impact and actual use by optical correction? I would be interested to see one or more as examples.
DavidBM wrote:
I think it’d be great if manufacturers have us both pre and post correction MTF charts.
I agree, otherwise it could be misleading when comparing MTF resolution within the same brand. One lens could have higher resolution but also higher distortion, so in reality, the numbers may not be what they appear. Having said that, I do think that distortion correction, especially normal barrel or pincushion, are not much of a concern when corrected in post but it's something to be aware when using a lens. For some scenes, distortion may actually benefit the final output. :-)
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So exciting!