Copy No.3 arrived last night: After some brief testing, I can say that the left corner looks better this time around. This copy is more uniform than the previous two, but I have to do some real-life shooting to see whether I can live with the corners at 70mm, which I'm still not completely happy with. Stopping down helps, but not as much as I'd like.
I have also realized that resolution in the outer areas begins to drop off somewhere between 50mm and 60mm. 50mm is still very good, not as good as the 55 1.8, but perfectly fine. Already by f5.0 (I haven't tested faster f stops yet), 24 and 35mm look excellent all the way into the corners.
Chris since your testing try a series by zooming to 70mm shoot that than back off to 50 than zoom back to 70 slowly and try that see if the 2 70 series match. I'm still in the belief of element groupings shifting depending how you get to 70mm.
GMPhotography wrote:
Chris since your testing try a series by zooming to 70mm shoot that than back off to 50 than zoom back to 70 slowly and try that see if the 2 70 series match. I'm still in the belief of element groupings shifting depending how you get to 70mm.
Are you saying you think that a slower creep up to 70 somehow enables it to be sharper?
Parariss wrote:
Are you saying you think that a slower creep up to 70 somehow enables it to be sharper?
I'm not sure but it is definitely a possibility. I have tested many zooms and sometimes a small change in focal length affects the corner area substantially. I've seen IQ differences when changing FL as little as 2mm with some lenses.
I don't own the 24-70GM any longer. Mine was severely damaged and I could never find a well-centered copy after many attempts. I pretty much gave up on it and that's a shame since my first copy was excellent. Most of the variation I've seen happens at the long range.
I've probably said this before, but I'm still having a hard time understanding why Sony continues to have this issue with it's lenses. Are they that inexperienced that they keep screwing up the design or manufacturing techniques? Are Canon and Nikon's techniques such a secret that they can't match them? With Zeiss as their partner you'd think they could solve these troubles. Or maybe, it's just us being too picky? Maybe 99% of their lenses that we find fault with are sold without complaints?
Fred Miranda wrote:
I'm not sure but it is definitely a possibility. I have tested many zooms and sometimes a small change in focal length affects the corner area substantially. I've seen IQ differences when changing FL as little as 2mm with some lenses.
I don't own the 24-70GM any longer. Mine was severely damaged and I could never find a well-centered copy after many attempts. I pretty much gave up on it and that's a shame since my first copy was excellent. Most of the variation I've seen happens at the long range.
So, Fred, the copies that you tried out before that did not perform to your liking in the corners then, I assume? How did they perform in the, let's say, 90% of the center frame. I came back from a trip where I used this lens a fair amount, even at 70mm and I am truly impressed with the center performance. Yes, at f/8 but we are talking prime lens sharpness and/or rendition here.
Steve most go unnoticed. Honestly very few people test their glass and many simply don't know how or care. Us pixel peeping anal as hell folks are kind of rare.
But as Fred mentioned even a couple mm in focal length issues can happen with zooms. My Nikon 14-24 was great on one hand and a piece of crap on the other . Focus shift and I suspect element shift as well. Zooms do not have very tight tolerances to begin with. Sloppy is a word I can come up with and not as tight in design as a prime. So these issues do exist in zooms.
stevesanacore wrote:
I've probably said this before, but I'm still having a hard time understanding why Sony continues to have this issue with it's lenses. Are they that inexperienced that they keep screwing up the design or manufacturing techniques? Are Canon and Nikon's techniques such a secret that they can't match them? With Zeiss as their partner you'd think they could solve these troubles. Or maybe, it's just us being too picky? Maybe 99% of their lenses that we find fault with are sold without complaints?
AGeoJO wrote:
So, Fred, the copies that you tried out before that did not perform to your liking in the corners then, I assume? How did they perform in the, let's say, 90% of the center frame. I came back from a trip where I used this lens a fair amount, even at 70mm and I am truly impressed with the center performance. Yes, at f/8 but we are talking prime lens sharpness and/or rendition here.
Yes, a good 24-70GM copy will give you great corners at f/8 and optimally at f/9. The same can be said about the FE 16-35/4 at 35mm...So, it's great if you stop down but the point is that it's the weakest focal length of this zoom.
p.49 #10 · Sony FE 24-70mm f/2.8 GM Rolling Review
stevesanacore wrote:
I've probably said this before, but I'm still having a hard time understanding why Sony continues to have this issue with it's lenses. Are they that inexperienced that they keep screwing up the design or manufacturing techniques? Are Canon and Nikon's techniques such a secret that they can't match them? With Zeiss as their partner you'd think they could solve these troubles. Or maybe, it's just us being too picky? Maybe 99% of their lenses that we find fault with are sold without complaints?
p.49 #11 · Sony FE 24-70mm f/2.8 GM Rolling Review
Totally agree. A 2.8 zoom lens covering pretty wide angel to mid-tele and equipped with 18 pieces glass and many aspherical elements, is not easy to make perfectly when compared with the simpler primes or zooms without extended lens barrels. Usually the lenses with best corner resolution are most criticized for decentering, because once there is a tiny decentering, it is so easy to see when compared to the other corners. Mirrorless makes pixel peering much easier than DSLR because of the very accurately focus and manual focusing friendly e-viewfinder.
My understanding is for such a standard zoom, boarder/corner quality at wide end is more important than tele-end. You can always crop to make it longer but not wider. Exchanging lens is a headache and time/energy consuming. So I will keep a decent one even the tele-end has some slight imperfection. You will never know what will be the next one like.
My new test showed my lens is good from 24-66mm, At 60-66, even wide open, the boarders are sharp when shooting 200mm away. it shows increasing decentering from 67-70mm. But this only affect foreground, because the outward field curvature aggravates the effect of slight decentering. I found focusing wide open, then stoping down really makes the boarder/corner sharper..
p.49 #15 · Sony FE 24-70mm f/2.8 GM Rolling Review
And even today, all zooms are fully optimized at only one FL, so the designers make their choice and live with the consequences. Due to magnification looking after longer FLs somewhat and the popularity of wide angle, Sony's is not a bad choice. C/N are destined for use by the pro market and need excellent 70mm image quality, as they will send a lot of time there - for people, corporate, etc.
Personal opinion - 50mm has to be excellent, fading gracefully wider and longer. Note you need f8-f11 for 'scapes at longer FLs in any case, lest you mistake insufficient DOF for poor corner definition. I feel that fewer zooms close in on the best WA primes but may approximate longer FL lenses more easily if designed to do so, due to greater optical correction in zooms and slower max apertures. Some even fade in the middle and have better wide and long IQ. A lot can be done in design. Sony should publish MTF at 24mm, 50mm and 70mm, to better inform the user base.
p.49 #16 · Sony FE 24-70mm f/2.8 GM Rolling Review
This lens seems to have a outstanding 50mm. Sharp and dead flat. 24mm is extremely sharp also, but there is a little CA in corner at contrasty setting. But that is already a lot better than the canon version in term of CA at 24mm.
I found this lens is only weak in the last a few mm for corner quality. the rest 95% of the FL, can be corner to corner sharp. And the bokeh is noticeably better than the Canon one. Canon actually is a shorter lens (24-65mm) with smaller and harsher bokeh ball at the tele end according to some reviews. But I don't have canon gears any more so can't compare them.
p.49 #19 · Sony FE 24-70mm f/2.8 GM Rolling Review
GMPhotography wrote:
Chris since your testing try a series by zooming to 70mm shoot that than back off to 50 than zoom back to 70 slowly and try that see if the 2 70 series match. I'm still in the belief of element groupings shifting depending how you get to 70mm.
Thanks for the tip, Guy. I tried but the result was not was I expected: The f8 image that I took first turned out to be sharper than the second I took after slowly zooming back in to 70mm from 50mm or so.
Fred Miranda wrote:
I'm not sure but it is definitely a possibility. I have tested many zooms and sometimes a small change in focal length affects the corner area substantially. I've seen IQ differences when changing FL as little as 2mm with some lenses.
I don't own the 24-70GM any longer. Mine was severely damaged and I could never find a well-centered copy after many attempts. I pretty much gave up on it and that's a shame since my first copy was excellent. Most of the variation I've seen happens at the long range.
Based on the crops posted in this thread, it seems that good copies are great even at 70mm. My third copy isn't de-centered, but even at f11 the extreme corners at 70mm stay soft. 24-50mm at infinity from f5 is excellent.
I'll probably spend the rest of my weekend pondering whether I can live with those crappy corners at 70mm or give up on the zoom and replace it with a fast 35mm and may be a Summarit 75.
p.49 #20 · Sony FE 24-70mm f/2.8 GM Rolling Review
Chris_88 wrote:
Thanks for the tip, Guy. I tried but the result was not was I expected: The f8 image that I took first turned out to be sharper than the second I took after slowly zooming back in to 70mm from 50mm or so.
Based on the crops posted in this thread, it seems that good copies are great even at 70mm. My third copy isn't de-centered, but even at f11 the extreme corners at 70mm stay soft. 24-50mm at infinity from f5 is excellent.
I'll probably spend the rest of my weekend pondering whether I can live with those crappy corners at 70mm or give up on the zoom and replace it with a fast 35mm and may be a Summarit 75. ...Show more →
Try 65mm on your latest copy and let us know.
Fred
