First test with my new Sigma 28-70 2.8


TPF Noob!
Jun 22, 2008
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Charleston SC
Can others edit my Photos
Photos OK to edit
Lit with a single sb800 shooting through umbrella.

Please critique.
I have ZERO people photography/studio skills, so I don't offer comments here, but.....

I do see what looks like posterization in his hair, left cheek and neck in particular - generally caused by heavy handed processing. Was he pasted into the background, or did you try to blur it more by any chance? What caused the overall blur?

OK, I'll shut up now.....


Forgot to add: Congrats on the new lens! That's always a thrill!
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The overall slight blur is shooting at 2.8, handholding probably below 1/60th.

You are right about the posterization though. I still haven't figured out how to avoid it, I was selecting the entire background with the magic wand to darken the BG, it was originally unbleached muslin.

Yea, to celebrate the acquisition of the new lens I added a Nikon 80-200 2.8 push pull to go along with it.
Why not bring the original, unaltered file here and let some of the post processing wizards show us both some tricks?

I know that I would learn learn from it, and I assume some other folks would too.

This image seem quite soft, I would suggest stopping down a bit and see if it is still soft.
If so return that lens!
This is no where near as sharp as it should be.
Yeah it's out of focus, and the posterization...did you do any shadow/highlight or fill light in post?

Cutting out backgrounds rarely ever works well and is never usually worth the trouble to get awful results unless of course you're shooting on a green screen, then it's easy and works great.

Instead of adding in a fake background, shoot outside, on location. There was another person on here who tried to do what you were doing and it looked awful, every time she posted people just kept essentially saying stop, these look horrible.

Just used this test chart and it is consistently showing moderate/severe back focus. I tried probably twenty different shots with different light and other angles and it was consistently off.


Going to go test all my other lenses to see if it's the body or just the one lens

My new (to me) 80-200/2.8ED and the sigma 28-70/2.8 are badly back focusing.

My Nikon 50/1.8 and sigma 70-300/f4-5.6 have an everso slight front focus, so minute that it could just be me and my crappy tripod.

I can't tell with the tokina 12-24/4 as I can't get just the chart in the frame, but the entire thing is sharp.
What camera you shoot with? can you do AF-fine tune?

otherwise, if it's 4 lenses with problems, i'd be suspecting that it's your camera body that's having the problems, not the lenses. try another camera with the lenses, even if it means going into a camera shop and testing it out on their cameras.
It only noticeable on my two new lense at 2.8. The Sigma 28-70 and an old 80-200 push pull.

it's barely noticeable (slightly forward) on my 50 at 1.8 and 70-300 at f4

I tested the sigma again at 3.2 and it was drastically better though, at f4 I'm starting to think it's sharper than my 18-105 was at f4 at 28mm.

I'm notn sure on the math though but looking at sigma's DOF chart for this lens it may be within their acceptable limits ......which sucks.
...what camera are you using?
yeah im seeing a lot of weird hard lines too.

i echo what sw1tch said about cutting people out of backgrounds...
Yeah, it wasn't pulled out of the background but rather using the magic wand to select the background and then darkening it, not as easy as it looks apparently.

As for the Body I'm using it's a D90.

I used the lens again this past sunday, shooting in good lighting in apertures from 5.6 to f8 and they were all crap on focus as well. I used my new to me 80-200 as far down as 3.5 and it was just rocking! sharp crisp focus exactly where I wanted it every time. All my other lenses as well.

I called up BHphoto, those guys rock! Instead of exchanging and waiting forever due to their passover closing, the offered me to return mine with free return shipping, sold me a new one with free 2 day shipping.

I just hope I don't get another one that's way off, I've been real happy with all of my other sigma lenses that I've owned.

I understand most manufacturers leeway in acceptable focusing but this one was way way off.
If you still have problems, do AF fine tune, pretty sure the D90 does that.

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