form wrote:
It is also not giving true f/1.4: I compared it to my 35l and the sigma at f/1.4 is about the same as the 35l at f/1.6. The sigma also shows only tiny fractional brightness difference between f/1.4 and f/1.6. I want to sell mine.
Wouldn't using a different focal length cause the camera to meter differently because of the FOV difference? It seems that is not a good way to test the sigmas t-stop unless I'm missing something
OK, I guess I was wrong when I posted earlier that I thought I had good copy. I have done a bunch of shooting this weekend and I can get my Sigma to focus on close subjects (3 to 7 ft) or more distant subject but not both. If I Microadjust so that close subjects will focus correctly, more distant objects will not. It is headed back to Amazon. Back to the drawing board.
vpexp wrote:
OK, I guess I was wrong when I posted earlier that I thought I had good copy. I have done a bunch of shooting this weekend and I can get my Sigma to focus on close subjects (3 to 7 ft) or more distant subject but not both. If I Microadjust so that close subjects will focus correctly, more distant objects will not. It is headed back to Amazon. Back to the drawing board.
Don't feel bad...Sigma lottery.
BTW: "Some" people who think they have copies that focus both close and far distances actually have OOF images in one or the other that is acceptable to "them". It can happen with any lens but Sigma seems to have a higher incident rate IMHO.
dfresh wrote:
Wouldn't using a different focal length cause the camera to meter differently because of the FOV difference? It seems that is not a good way to test the sigmas t-stop unless I'm missing something
I shot in manual with identical camera settings and the same subject, and the histogram and visual image in camera review both showed the sigma image was darker in the same area of the image and overall.
MrAdventure wrote:
BTW: "Some" people who think they have copies that focus both close and far distances actually have OOF images in one or the other that is acceptable to "them". It can happen with any lens but Sigma seems to have a higher incident rate IMHO.
MrAdventure wrote:
Canon should be listening...make the 50 1.4 a bit more "robust" and these discussions would be moot.
Well, to an extent. To be completely honest I think both lenses have their issues, and for the EF 50/1.4 it doesn't stop at build quality. AF speed and accuracy is not as good as it should be with either lens, especially in low light. The Sigma has great build and better bokeh...if it had a true USM motor it would be a killer lens. The only thing the EF 50/1.4 has going for it is better consistency (decent but not excellent)...it could use a lot of work otherwise. Give me a Canon 50, 55 or 60mm with either an f/1.4 or f/1.2 aperture with a 9 blade design, solid build, full USM motor with no goofy focus shift issues and I'd be golden
MrAdventure wrote:
BTW: "Some" people who think they have copies that focus both close and far distances actually have OOF images in one or the other that is acceptable to "them". It can happen with any lens but Sigma seems to have a higher incident rate IMHO.
M Vers wrote:
Agreed.
Sorta like 50L users who claim that their copy doesn't suffer from focus shift
"Give me a Canon 50...with either an f/1.4 or f/1.2 aperture with a 9 blade design, solid build, full USM motor with no goofy focus shift issues and I'd be golden..."
I loved my Sigma 50mm f1.4, I spent ages tracking down a decent one second hand and was very pleased with it. Then I bought the Sigma 30mm f1.4... I've barely touched the 50mm since, I can't bring myself to sell it on so bought an old EOS 3 to use it on
abam wrote: "Give me a Canon 50...with either an f/1.4 or f/1.2 aperture with a 9 blade design, solid build, full USM motor with no goofy focus shift issues and I'd be golden..."
Worth every moment of the hassle to get a good copy.
I like that...
Know the hassle I went thru to get my 50 & 85?
I searched Craigslist, found two sellers, contacted them and within 4 hrs we swapped cash for the glass. Tested them both very briefly at the exchange location and then went home and shot two sessions with them. Focus, condition, results...perfect.
No MA, no sending them in for calibration...nothin'.
Not saying Sigma doesn't make nice swag. They just aren't reliable from one copy to the next.
Except for the 24-70 L, I have not seen this much discussion on the frustrations of any lens.
I tried two Canon 50 1.4 and returned them as neither would focus past 10 feet. Got the Sigma today after a brief test at the camera store. It seems to be working well but I will have to check more closely when I get to the studio tomorrow. I did get a few front focused images when shooting in low light but I really can't tell if I am at fault or if the lens fails at low light.
What really puzzles me about AF is the idea that somehow the lens is moved to a specific position based on what the AF module says. I always thought it was based on a contrast detection process that would stop the motor at the point of greatest contrast (i.e. sharpest). Thus calibration would be irrelevant as the AF would be self correcting.
What is really going on? And why will one lens hunt while another snaps into focus?
It seems that all of these threads play out the same way, with some lamenting the AF issues with
the Sig 50 and others raving about how theirs has never had a problem. I tend to believe both
camps. I happen to be one who has had problems. Sigma had my lens and my Canon 5D body
for about a month and after speaking with the supervisor who assured me it was in the best
condition he could get it, they sent it back. It seems to be about the same as when I sent it in.
I don't worry about it much anymore. I treat the lens as one that can really deliver the goods
if I baby it and focus-bracket and such. Frankly, I still think it's a good lens, but yes it has
made me reluctant to even bother trying the Sig 85, even though I'd love a great 85/1.4 with AF.
But that's it: It needs to have reliable AF, and for the moment I'm not interested in rolling the
dice to see if Sigma got it right. I am happy for those whose copies are great. [This is not just
a Sigma issue either. I am reluctant to buy a lot of high-precision gear these days -- Canon
included, because it does, in my experience, require testing and occasional trips to service to
get tip-top performance.]
By the way -- my Sigma 150/2.8 macro works fine, so Sigma sometimes gets it right too. I'm
not trashing Sigma.
After all the glowing reviews I really wanted to find a good copy of sigma 50 but after returning 3 copies to B&H I gave up and got canon 1.2. Every copy of Sigma that I tried could not focus even close to accurate and they were all off by sufficient margin that microadjust would not help.
I like that...