Purchasing Sigma 35 f/1.4: how to know it is a good copy?

Community, I wanted to ask what is the way to test this lens properly based on your experience to date? I will only have 7 days to return in case something is wrong with it, but I will probably need to verify in areas where you know the lens might struggle. Also if you can suggest how do I test it in the 7 days I have, I will appreciate.
Thanks!

try one on these on steady tripod
https://www.google.com …fficial&safe=of​f&tbm=isch

majix wrote in post #16483154
try one on these on steady tripod
https://www.google.com …fficial&safe=of​f&tbm=isch

This can be done, yes. I hear that AF has problems in various lightning conditions. True?

light_pilgrim wrote in post #16483249
This can be done, yes. I hear that AF has problems in various lightning conditions. True?

I've only heard that from 1 or 2 users on this forum. Mine doesn't have that problem. I think its fluorescent lighting vs sunlight that produces different results for those people, but I can't remember for sure.

light_pilgrim wrote in post #16483249
This can be done, yes. I hear that AF has problems in various lightning conditions. True?

I've been testing a Sigma 35 1.4 against my 35L for the last couple of weeks. I'm actually thinking of replacing the L with the Sigma.

The Sigma is awesome optically, but (imo) it is not quite on par with the Canon for low light AF. It's hard to accurately describe light levels on a forum, but (with the 5D3) the Sigma starts to struggle in the ISO3200 f/1.4 1/80 and below range...basically dim indoor lighting with no AF assist beam. The hit rate drops significantly and the AF seems to hesitate...it seems to get close to being in focus and then there is a little delay before you get an AF confirmation light. The Canon is relatively fast and accurate down to around the ISO3200 f/1.4 1/40 range, and below that they both struggle (which probably says more about the 5D3 than either of the lenses). To put it in other words, I would probably give the Canon a 1 stop advantage for AF performance, if that makes any sense. This is going more on feel than formal testing...but I shoot a lot with fast primes in dim lighting, ymmv.

So, if you think dim indoor lighting with no AF assist beam is a situation you'll be shooting in often, I would try to get a feel for how the Sigma performs there. In brighter, more contrasty light or with an AF assist, in my experience it's been hard to distinguish the AF performance from the Canon.

Use the lens exclusively for a day or two, in the conditions that you typically shoot. Then look at the images on your computer screen at the sizes you think need them to be looked at. If everything is fine, then the lens most likely is ok.

Shoot under various lighting types. The only problem I've I remember hearing about with this lens is focusing issues is under artificial lighting and/or low light.

If for some reason you need more - use a tripod and do some lens test, there are plenty out there. Here's one with some directions and advice. Here's another! Here's a third with related links. If you are that worried, pick a test and do a series of shots each under natural, then incandescent, then fluorescent, then mixed lighting for this lens. I would think that should cover it.

I have the 35L, but have and have had other Sigma lenses (though never the 35 Art). Mine is sharp enough for me, so I currently don't see any reason to sell and get the Sigma. BUT I have not had issues with Sigmas, other than the OLD Sigma lenses and their lack of compatibility at all aperture (wide open works) on the digital cameras. I would not hesitate to get a Sigma lens if it fit my needs.

I replied to you in the Sigma 35 thread...

https://photography-on-the.net …p=16483615&post​count=3549

MakisM1 wrote in post #16483621
I replied to you in the Sigma 35 thread...

https://photography-on-the.net …p=16483615&post​count=3549

Thank you very much. Got the lens It focuses better than my ex-Zeiss 35 F/1.4 for sure. I will not have time to test until the weekend, but I just took couple of shots at home...deem light...ISO 800 and I think it is reasonable. Might be a bit slower to focus than my Canon lenses...but I actually never paid attention, It is a very low light situation, so I am sure it will be very different during the daylight.

Thanks again, sir Not sure what I will be able to produce, but I will do my best. It feel like a great product that is just a pleasure to use. Impressed with the quality of design, feels like Zeiss and it has great IQ and also AF. Sigma has done a very-very good job. Impressed with them.

community - THANK YOU for suggestions. Everything is exactly what I needed. Got the lens...just did 5 shots...low light...some books and coffee mugs. Looks OK for what I was able to test. Will give it a proper run during the weekend.

I think Sigma did a very-very good job with this lens. Feels great...this lens.

light_pilgrim wrote in post #16483821
community - THANK YOU for suggestions. Everything is exactly what I needed. Got the lens...just did 5 shots...low light...some books and coffee mugs. Looks OK for what I was able to test. Will give it a proper run during the weekend.

I think Sigma did a very-very good job with this lens. Feels great...this lens.

Glad it seems good so far, hope (an think it will) stay that way. Good testing this weekend.

light_pilgrim wrote in post #16483140
Community, I wanted to ask what is the way to test this lens properly based on your experience to date? I will only have 7 days to return in case something is wrong with it, but I will probably need to verify in areas where you know the lens might struggle. Also if you can suggest how do I test it in the 7 days I have, I will appreciate.
Thanks!

Heya,

Take images at wide open aperture and check where it focuses.

Very best,

Somehow I cannot force myself to test with charts Maybe when I will see that something is wrong, I will be forced to. For now...it is OK.

So I wanted to test the lens and as folks suggested, I just went out and used it the way I would normally use. Actually....I had really poor conditions to test it - very cloudy, grey day...raining all the time. I asked one of my friends to help and she agreed.

I took couple of shots today...indoor, all with ISO 800, either f/1.4 or f/1.8 and a shutter speed between 1/60 and 1/100.

I do not know, it looks fairly OK for me. I just wanted to see that if I will want to focus on the right eye, it will be sharp and I think it looks good. I would prefer to test it outdoor and with better conditions, but it i what it is. I am happy for now. I owned a Zeiss 35 F/1.4 ZE and I have to say that Sigma is as good, comes with AF and costs half the price.

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i received a bad copy last week and followed some advices on this forum (i really appreciate that)

shot a chart using a tripod and the liveview with x10 zoom on to make sure the focus point is the most accurate

finally returned the lens and order a new, redid the test, results were good

but i would gladly borrow this girl to redo some focus tests

It look good to me!

macaron95 wrote in post #16490818
but i would gladly borrow this girl to redo some focus tests

I really did not have a lot of opportunities to photograph with this lens...only what I did today. But it looks OK....I think it would already show me problems if something was wrong. I did not do any adjustments...just used it straight away and it looks like eyes are in focus.

It will be much easier when the light is better.

Yes, I agree with you...it is a lot more pleasing to have a friend posing than shooting a chart, but you gotta do what you gotta do