p.29 #1 · Sigma 14-24mm f/2.8 DG DN first impressions
Matti6950 wrote:
Very nice images, theacguy71
This is the type of shots, that i also would take with my nikon 14-24mm. Haven't used it much because, i get a lot of soft images with it (focus shift, or just bad copy) dunno, also LOTS of flare. and no lifeview focus. I'm now migrating to Sony. This is one of first lenses i will buy. The MTF just blows away zooms, and is also competitive with primes. And it's still less weight then DSLR, function button, etc.
@Fredmiranda@, you mention good flare resistance. Maybe this has something to do with the newly advertised Nano Porous Coating. Sigma usually doens't overstate something, that is 'not worth it', so i believe them when they made newly improved coating....Show more →
I think that flare resistance is quite good for this type of lens and that was a surprise to me. I've tried many ultra wide zooms like the Canon 11-24, Nikon 14-24, Tamron 15-30, Sony 12-24 and imo the Sigma has by far the best flare resistance. (prime-like)
p.29 #2 · Sigma 14-24mm f/2.8 DG DN first impressions
rvh23 wrote:
If you focus on only one corner, and don't refocus when you look at the other three corners, you will see any tilt. That is the method I am advocating. If you are being very fussy, which I tend to be, I think the Loxia 21 is actually a good candidate for using this method over center focus.
Sure, that’ll work too!
I like the checking outer midframe on either side of central focus as well , because that gives a good sense of the degree/destructiveness of tilt. With some very fast lenses you’ll see very small amounts of tilt and it’s good to check how strong it is and whether it has much effect closer than the 20mm point.
p.29 #3 · Sigma 14-24mm f/2.8 DG DN first impressions
rvh23 wrote:
If you focus on only one corner, and don't refocus when you look at the other three corners, you will see any tilt. That is the method I am advocating. If you are being very fussy, which I tend to be, I think the Loxia 21 is actually a good candidate for using this method over center focus.
Agree. I test the Loxia 21 by setting the focusing ring at the hard stop which means best corners for all copies I've tried. I sold mine a while back and I'm having a hard time finding a replacement performing at the same level.
Sunny day today, so I took some time to put in practice the decentering tests of my new Sigma 14-24 f2,8 DG DN.
I carried out Fred Miranda's method and also, inmediately after, the RVH23's method. Both of them at 14 mm@f2,8, no postprocessing and no sharpening (LR defaults)
Honestly I think that regarding the RVH23's method, my lens is a keeper. But reviewing the results from Fred Miranda's method, maybe I should get rid of my copy and try another one, wishing some better luck this time.
What do you think about it? Am I missing something putting in practice both methods? Why are they so discrepant?
I followed strictly FM instructions and also RVH23 guidances.
If I think about the words that RVH23 wrote yesterday, regarding that his method avoids field curvature blurring, it is really possible that what I see in FM method is the effect of field curvature at 14mm.
Thanks a lot!
Best
PS. By the way, at f8 all the extreme corners are equally very very sharp. Almost undistinguishable from center frame.
p.29 #5 · Sigma 14-24mm f/2.8 DG DN first impressions
JeyB wrote:
Hi again
Sunny day today, so I took some time to put in practice the decentering tests of my new Sigma 14-24 f2,8 DG DN.
I carried out Fred Miranda's method and also, inmediately after, the RVH23's method. Both of them at 14 mm@f2,8, no postprocessing and no sharpening (LR defaults)
Honestly I think that regarding the RVH23's method, my lens is a keeper. But reviewing the results from Fred Miranda's method, maybe I should get rid of my copy and try another one, wishing some better luck this time.
What do you think about it? Am I missing something putting in practice both methods? Why are they so discrepant?
I followed strictly FM instructions and also RVH23 guidances.
If I think about the words that RVH23 wrote yesterday, regarding that his method avoids field curvature blurring, it is really possible that what I see in FM method is the effect of field curvature at 14mm.
Thanks a lot!
Best
PS. By the way, at f8 all the extreme corners are equally very very sharp. Almost undistinguishable from center frame. ...Show more →
I think you should test the 14-24mm at least at 14mm and 24mm. (Perhaps a FL in between as well)
Field curvature should not matter as there is minimal curvature with this zoom anyways.
Make sure IBIS is turned "Off' and it may be a good idea to use manual exposure so we don't see any change in exposure between frames.
If you didn't have IBIS "on", your results shows it's not perfectly centered but still pretty good for a zoom. If you can, do a test for 24mm as well.
There is no perfect zoom so if you can get similar results at 24mm, it may be a keeper.
p.29 #6 · Sigma 14-24mm f/2.8 DG DN first impressions
Hi Fred!
Thank you very much for your answer. I also really took those shots this evening at 14, 18, 20 and 24 mm. I choose an antenna at about 70-80 meters from me.
Enclosed are the tests shots with your method. I apologize if they are not perfect. It was my first time
The shots were taken in manual exposure, same speed (about 1/2500) and ISO100, can't remember if IBIS was on or off.
Hmm I think I should have compensated for some exposure inconsistencies when recomposing. It was my first time with the camera upside down and I felt somewhat strange, like people walking should think while looking at me
p.29 #9 · Sigma 14-24mm f/2.8 DG DN first impressions
JeyB wrote:
...or maybe it is not camera shake, can't be sure. By the way IBIS was on. Should I repeat with IBIS off?
I am completely lost with these tests
Yes, repeat with IBIS 'off'. With wide focal lengths, IBIS can be an issue.
If you have manual exposure, you don't need to compensate. Just do it for 14mm and 24mm. If it passes these two focal lengths, consider yourself lucky!
p.29 #11 · Sigma 14-24mm f/2.8 DG DN first impressions
Fred Miranda wrote:
Yes, repeat with IBIS 'off'. With wide focal lengths, IBIS can be an issue.
If you have manual exposure, you don't need to compensate. Just do it for 14mm and 24mm. If it passes these two focal lengths, consider yourself lucky!
Hello Fred!
Today in the morning I carried out the test shots you asked me at 14 and 24 mm. IBIS OFF, manual exposure, ISO400, 1/3200. Cloudy day, but I think the shots will serve to assess if my copy is a keeper or not.
I've shot at 14, 18, 20 and 24mm FLs. But as you suggested, I only link the 14mm and 24mm ones for your scrutiny. If you also want to see, for further evaluation, the 18 and 20mm results, I have them here. I don't want to polarize this thread nor disturb you of course.
What I see is that 24mm is the weakest FL, and it shows some kind of astigmatism-like effect at the top right corner crop. It begins to show it mildly at 20mm, but at 24mm it is more evident. I will use this lens mainly for architectural and interior design shootings.
p.29 #13 · Sigma 14-24mm f/2.8 DG DN first impressions
JeyB wrote:
Hello Fred!
Today in the morning I carried out the test shots you asked me at 14 and 24 mm. IBIS OFF, manual exposure, ISO400, 1/3200. Cloudy day, but I think the shots will serve to assess if my copy is a keeper or not.
I've shot at 14, 18, 20 and 24mm FLs. But as you suggested, I only link the 14mm and 24mm ones for your scrutiny. If you also want to see, for further evaluation, the 18 and 20mm results, I have them here. I don't want to polarize this thread nor disturb you of course.
What I see is that 24mm is the weakest FL, and it shows some kind of astigmatism-like effect at the top right corner crop. It begins to show it mildly at 20mm, but at 24mm it is more evident. I will use this lens mainly for architectural and interior design shootings.
Hi JeyB,
I think it looks very good for a zoom lens and unlike primes, we can't expect perfection. I think turning off IBIS made a difference for 14mm.
24mm looks centered although not perfect but I doubt you will notice any discrepancies when shooting real world images. (even astro)
It's a very hard test for any lens. It's rare when all 4 corners look symmetrical even when testing high quality primes. Consider yourself lucky.
p.29 #15 · Sigma 14-24mm f/2.8 DG DN first impressions
I got just got this info from the newsletter of the Aurora Kickstarter Project:
"Finally, we announce development of rear glass filters for the Sigma 14-24mm F2.8 DG DN Art for Sony FE mount. We expect general availability in December 2019. There will be several strengths of ND filters and light pollution reduction filter."
Since their glass filters will definitely be thicker than the Lee gel filters Fred had tested, they will have some effect on corner sharpness and FC. How much, we will see. At least for their Kickstarter filters they plan to use filter glass with 55% reduced thickness.
p.29 #16 · Sigma 14-24mm f/2.8 DG DN first impressions
Bobu wrote:
I got just got this info from the newsletter of the Aurora Kickstarter Project:
"Finally, we announce development of rear glass filters for the Sigma 14-24mm F2.8 DG DN Art for Sony FE mount. We expect general availability in December 2019. There will be several strengths of ND filters and light pollution reduction filter."
Since their glass filters will definitely be thicker than the Lee gel filters Fred had tested, they will have some effect on corner sharpness and FC. How much, we will see. At least for their Kickstarter filters they plan to use filter glass with 55% reduced thickness.
It needs to be thin enough to even fit inside the rear slot groove and for the locking slider to clear with the filter inside.
I can't see how glass can be that thin but I'm definitely curious about it.
Do you know if it will use the Sigma slot or if they will have an adapter similar to how their rear filters work with IRIX and Canon lenses?
p.29 #17 · Sigma 14-24mm f/2.8 DG DN first impressions
Fred Miranda wrote:
It needs to be thin enough to even fit inside the rear slot groove and for the locking slider to clear with the filter inside.
I can't see how glass can be that thin but I'm definitely curious about it.
bhphotovideo.com/c/product/1347938-REG/aurora_aperture_pnd_ir_kit_aurora_ir_format_powernd.html/reviews
Do you know if it will use the Sigma slot or if they will have an adapter similar to how their rear filters work with IRIX and Canon lenses?
It's available with thickness from 0.03mm - 1.1mm. If they use some of the ultra thin versions it will probably fit but robustness will clearly be a problem. No idea whether they plan to use the Sigma slot or build some adapter on top.
But if they announce the development they should at least have some idea how to realize this.
Of course, you have to remove the foil from the plastic holder and cut them, but that's no big problem. They cost around 50€ (set of three), which is close to the Kodak Wratten filter price (for a single filter).
