Sigma 85mm 1.4 EX DG HSM vs. Nikon 85mm 1.8 D

Received this question from a reader, I don't have experience with these lenses so I figured I would post the question to see if anyone has recommendations for her.

"I mainly shoot my son's wrestling matches (action, low-light) with my Nikon D700. My current lenses are: Nikon AF-S 24-70mm f/2.8G ED, Sigma 85mm f/1.4 EX DG HSM, Nikon 50mm f/1.8 G, and a Nikon AF 28-200mm f/3.5 ED
*************************
I recently purchased a Sigma 85mm f/1.4 EX DG HSM. I've only had it a week, but I am wondering if I made a mistake. I've been reading that the Nikon 85mm 1.8 D has a faster focus. The reason I need something with a such a large glass is that when we go to our state tournament, NO FLASH (for any reason) is allowed. These tournaments start at 8am and can last as late as 7pm. I was using my 200mm Sigma 2.8 (sold it this year) and my Nikon 50mm 1.4 G (which I've also sold) both with "OK" results and both lenses giving a lot of BLUR. Not being able to use a flash at this state tournament is killer. I had the ISO pretty high (800 I think). I did not want a lot of grain (unusable) images.
*****************************
So is anyone aware of which one of these lenses would be better for being to work in the low-light environment, but still fast enough to capture the action without blur?
sigma 85mm 1.4 EX DG HSM vs. nikon 85mm 1.8 D
******************************
p.s., This year he will be doing Discus Throwing. Anyone have a lens suggestion"

Any info or insights would be greatly appreciated. I will direct her to this forum. Thanks :)

Tags: lenses

0 members like this

▶ Reply to This

Replies to This Discussion

Permalink Reply by CameraClicker on August 19, 2011 at 3:40pm

I have Canon dSLR's and thus have no direct experience with any of the lenses she mentions. I have some Sigma lenses and have lenses with the apertures she mentions, and I shoot in low light without flash fairly frequently.

She raises a number of points:

She has had fast glass and has not been able to achieve the desired result.

She would like a lens that focuses quickly

She does not want a lot of grain, so she is keeping ISO at 800 or below.

She will be at a venue that does not allow flash to be used.

Blur comes from a three sources, the camera moved, the subject moved or focus was not on the subject. By looking at the past photos she can determine which was the cause based on where the blur is and the shape of the blur. If the blur is caused by subject movement, the only cures are to use a higher shutter speed or to release the shutter when the subject is not moving. Wrestling may have changed but what I remember from school leads me to believe that a lens with faster focus is mostly irrelevant. Two people are on a mat and move very little in relation to the camera. Depth of field and shutter speed are more important. f\1.4 will give very little depth of field but f/1.8 will not give much more. f/1.4 will give a slightly faster shutter speed. To stop blur of hands, a shutter speed of 1/60 or 1/125 will probably be necessary.

In the circumstances, the key to stopping blur is visiting a place she does not want to go: high ISO.

My advice is to use either lens, shoot raw, increase ISO to at least 1600 and perhaps even 3200 or 6400 -- do some testing in similar light if possible before the next important photo session -- and use some good noise reduction software while converting from raw to jpg. The best software I have used is the version of Adobe Camera Raw which comes with Photoshop CS5 and Lightroom 3. Noise Ninja is a package which I have heard good things about but have not used. If high ISO values are still limiting, shoot some bursts and pick the image with the least blur, which will probably correspond to when movement of the subjects stops briefly, or slows.

Regarding a lens for Discus Throwing, the same things need to be taken into account, how far away is the photographer/what focal length is needed, how much light is available, what is the desired shutter speed and aperture, can it be achieved with an available ISO setting.

▶ Reply

Permalink Reply by Alan Ang on August 21, 2011 at 4:43am

From what I know f1.4 is definitely better than f1.8 as the aperture is bigger and allow more lights to enter the camera thus suitable for low light environment shooting. as for brand comparsion Nikon will be better than sigma in term of quality manufactured. One has to try out both len to be able to tell.

▶ Reply

Permalink Reply by CameraClicker on August 21, 2011 at 7:22am

The Wikipedia page - http://en.wikipedia.org/wiki/F-number - shows that f/1.4 is two thirds of a stop faster than f/1.8. Is that enough to matter?

Here is a table for a given light source that steps through ISO from 200 to 6400 and the shutter speeds available at f/1.4, f/1.8, f/2.8 and f/4 for each ISO setting.

ISO	f/1.4	f/1.8	f/2.8	f/4
200	1/60	1/45	1/15	1/8
400	1/125	1/90	1/30	1/15
800	1/250	1/180	1/60	1/30
1600	1/500	1/350	1/125	1/60
3200	1/1000	1/750	1/250	1/125
6400	1/2000	1/1500	1/500	1/250

Remember that depth of field is very shallow at f/1.4 and almost as shallow at f/1.8. This makes these lenses very popular for portraits because you can get the eyes in sharp focus and the ears will be less sharply focused. Everything behind the subject will be out of focus. Typically a lens is not as sharp wide open as it is closed down a stop or two, but if you are starting with a lens at f/1.4 or even f/1.8, by the time it is closed down to f/2.8 it will typically be very sharp, but depth of field at f/2.8 is still relatively small at medium and long focal lengths.