What would give me a sharper picture?

I am debating and have been testing but not sure which should be better..

For pictures of very low light, static objects, hand held, which lens would give me better results?
- canon 15-85 ( 4 stop IS @ 30mm ~ f4.5)
- Sigma 30 f1.4 (stopped down to f1.8 for some sharpness)

Do you need IS, how much would it help kind of depends on your ability to hold the camera/lens still. Static subject - is a mononpod, tripod a possibility?

From your sig line, it looks like you should be showing us the results instead of asking the question.

FEChariot wrote in post #16072413
From your sig line, it looks like you should be showing us the results instead of asking the question.

Good point!

I am on vacation with family... So don't have much time to test.
I am doing night time low light pics and on my camera it's hard to see until I get home to upload and look at a big screen.

So I would like to know people's experience... That way I can use the right lens right away without swapping all the time and having my wife give me "the look"

And tripod is not an option....

Lexar wrote in post #16072406
For pictures of very low light, static objects, hand held, which lens would give me better results?
- canon 15-85 ( 4 stop IS @ 30mm ~ f4.5)
- Sigma 30 f1.4 (stopped down to f1.8 for some sharpness)

15-85 from just the sharpness point of view. Also more dof on subject will give you the illusion of being sharper.

Sigma 30 might not be as sharp, however it gives you a totally different effects and looks. So it really comes down to what you are trying to achieve.

Lexar wrote in post #16072406
I am debating and have been testing but not sure which should be better..

For pictures of very low light, static objects, hand held, which lens would give me better results?
- canon 15-85 ( 4 stop IS @ 30mm ~ f4.5)
- Sigma 30 f1.4 (stopped down to f1.8 for some sharpness)

the Sigma 30mm is going to be significantly sharper (prime !) especially in low light but the zoom is more practical

watt100 wrote in post #16072570
the Sigma 30mm is going to be significantly sharper (prime !) especially in low light but the zoom is more practical

Wrong...

http://www.the-digital-picture.com …omp=0&FLIComp=0​&APIComp=2

Zoom @ 35mm f4.5 (no 30mm on the site), prime @ f2.

The zoom demolishes the prime in terms of pure sharpness.

kin2son wrote in post #16072627
Wrong...

http://www.the-digital-picture.com …omp=0&FLIComp=0​&APIComp=2

Zoom @ 35mm f4.5 (no 30mm on the site), prime @ f2.

The zoom demolishes the prime in terms of pure sharpness.

dude, those are at different apertures and different focal lengths !
your comparison is invalid

Try comparing MTF sharpness numbers at the same aperture and same focal length and see how one "demolishes" the other
hint: it ain't the zoom on top!

Thanks!

I was looking more on the very low light aspect, hand held aspect...

What would work better... Large aperture f1.8 or 4 stop IS but f4.5

watt100 wrote in post #16072644
dude, those are at different apertures and different focal lengths !
your comparison is invalid

Dude read OP's question!

He wants to know which is sharper, zoom @ 30mm f4.5 vs Sigma 30 @ f1.8, NOT 15-85 vs Sigma 30 @ f4.5.

The link I posted sure the zoom is at 35mm, but there will be no difference @ 30mm.

I set the prime @ f2.0 which should be already sharper than what OP wants to compare with (ie f1.8).

Result - Zoom is sharper in that given scenario.

Lexar wrote in post #16072652
Thanks!

I was looking more on the very low light aspect, hand held aspect...

What would work better... Large aperture f1.8 or 4 stop IS but f4.5

Better in what way?

Sharpness - Zoom.

Creativity or artistic value/bokeh - Prime!

You stated in your first post that your subject is static low light, therefore zoom will give you sharper result.

But sharpness doesn't necessarily mean a better or more pleasing result!

And if your subject moves, you're gone with the zoom...

Personally, I'd go with the IS, as long as your body can lock on the focus in very low light with 4.5. If not, then definitely go with the 1.8, so you can AF it.

Yes for anything that might have motion the prime would be better!
But I am talking static architecture.

Real example is a picture of buildings, very low light, handheld with:
prime Sigma30 at f1.8 with 1/13 sec.
Versus a picture with zoom 15-85 at f4 with .4 sec. (4 stop IS)

So what be clearer and sharper?

Lexar wrote in post #16072722
Yes for anything that might have motion the prime would be better!
But I am talking static architecture.

Real example is a picture, very low light, handheld with:
prime Sigma30 at f1.8 with 1/13 sec.
Versus a picture with zoom 15-85 at f4 with 4 sec. (4 stop IS)

So what be clearer and sharper?

the other poster has a point, there is greater depth of field "DOF" at f4 than f1.8 and for buildings that's better. And shooting at 1/13 is problematic. But set both to f4 and of course the prime is going to be sharper.

(for me) I almost always use the Sigma 30mm 1.4 for low light situations, e.g.

Sigma 30mm @ f1.4 1/40, iso 2200

Lexar wrote in post #16072722
Yes for anything that might have motion the prime would be better!
But I am talking static architecture.

Building and architecture? Zoom hands down! No contest.

/thread