[mgoblue]

I would think whether 2.8 zoom with flash or 1.4 prime gets better candid photos depends on one's style and desired result. For me, flash is not suitable for candid work. People notice it, which makes candid difficult. And I love the play of light from natural and room light sources in candid photos --- flash can make technically better lighting, but not necessarily better art. I also often like my subjects isolated which is more difficult at 2.8 on APSC. Control over depth of field is big for me. But others like different looks. That's the beauty of photography as an art.

[MSL]

Maybe it is just me, but I think that f/1.4 for "candid" would work only if the child do not move. There so thin deph of field at f/1.4 that you'll have many blurred shoots, even with a still subject you'd have to take care and have at least K5-II or K3 in dim light.

I have to agree with this in terms of shooting kids. I've used a 50/1.4, and for fun will try to capture them but knowing I'm playing a tough game. I'm lucky if 1 shot in 20 is sharp, although when it is you do get a lovely portrait out of it. For shooting real portraits I've used a 50/1.7 AF in low light. Even then I'll try to shoot f2 or f2.4 just to get some depth of field.

[mgoblue]

A 30 of course gives more depth of field than the 50. F2 Typically gets a face in focus very easily. My keeper rate as far as auto focus on the Sigma is excellent, but also lower at 1.4. Still, I used to use bulk film back in the day and print loads of contact sheets in a darkroom -- with digital it is even easier to rattle off shots. Firing away and practice over decades helps. Live view and manual focus can help too.

Anyway OP I hope you tell us how you enjoy the Sigma if you do pick one up! It's a good value and it might suit your style or not, but it's not too expensive to find out and play with for a while. I'd be very interested to hear how you find it next to your 85.

[mannyquinto]

You wont regret getting the Sigma 30. I used mine on my children and had a lot of keepers. If your going to get a 2nd hand copy, just make sure to test it first and if you ever need to use focus adjustment it should be within the range. I brought mine locally and had it calibrated with my K-x. On my K5ii its spot on.

[MSL]

A 30 of course gives more depth of field than the 50.

A 30 shooting an object 6 feet away at 1.4 will have the same DOF as a 50 shooting an object 10 feet away at 1.4.

[mgoblue]

Yes for a given film size. I use my 30 1.4 as I used my 50 1.4 on film. So it provides more depth of field / less control, but still a bunch more than 2.8 which is really very broad in depth field and hardly fast on APSC. That's my point about needing the 1.4 30 on APS for how I shoot. But also moving the distance to the subject does change perspective so one does not necessarily fill the frame the same way.

[alexbird]

I have to agree with this in terms of shooting kids. I've used a 50/1.4, and for fun will try to capture them but knowing I'm playing a tough game. I'm lucky if 1 shot in 20 is sharp, although when it is you do get a lovely portrait out of it. For shooting real portraits I've used a 50/1.7 AF in low light. Even then I'll try to shoot f2 or f2.4 just to get some depth of field.

Sure it's never easy to take candid shot. At F2~F2.4 I go around 1/10 good shot in both well focused and good expression.

Anyway OP I hope you tell us how you enjoy the Sigma if you do pick one up! It's a good value and it might suit your style or not, but it's not too expensive to find out and play with for a while. I'd be very interested to hear how you find it next to your 85.

Thanks, certainly I'll. I'm seeking someone in good price/condition. I think the most challenge may be the perspective, since I'm used to shot shoulder portrait. I ever tried FA*24 but found it's hard to composition and my girl looks worse than 85... Check these two:

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Last edited by alexbird; 09-14-2014 at 07:06 PM.

[mgoblue]

Those are great! Beautiful daughter and a special lens. I've not tried it on APS but now suddenly you are convincing me that I need a new lens ;-). I often think the older glass renders better -- in addition to the perspective advantage of the 85.

You should get the same perspective with the 30 on APSC as the 50 (i guess a 45) on film. I haven't looked at the tests but in my experience it seems with more barrel distortion on APSC 30 which is not so flattering. The 24 would be more like a 36 on film so unflattering perspective would be a bigger issue. 50 on film is not as kind as 85 but it is natural and so with 30 on APSC. The 30 1.4 has kept me satisfied with APSC as it is nearly a 45 1.8 from film, which was great. It is much bigger in size and it isn't quite as glorious b/c:

To MSL's point even when the depth of field and f stop are exactly the same, the background blur of the 45/50 will be blurrier on film than the 30 on APSC. I think that is probably the main reason the old film lenses seem to render better to me. 50 is always longer than 30 and so will blur more at the same depth of field. It makes having that 1.4 on APSC even more valuable. Unless I've gotten really confused... I need to go take more pictures instead of thinking about this!

[MSL]

To MSL's point even when the depth of field and f stop are exactly the same, the background blur of the 45/50 will be blurrier on film than the 30 on APSC. I think that is probably the main reason the old film lenses seem to render better to me. 50 is always longer than 30 and so will blur more at the same depth of field. It makes having that 1.4 on APSC even more valuable. Unless I've gotten really confused... I need to go take more pictures instead of thinking about this!

I agree - go take some more pictures. Just to clarify - my point wasn't about blur - it was more about difficulty of catching a toddler or young child using a 1.4 aperture with an focal length.