- Feb 22, 2001
- 3,044
- 544
- 136
A few months back, I picked up a new Sigma 17-70 f2.8-4.0 lens.
I wanted something a faster than kit lens, with similar if not better focal distances.
Reviews on this budget (compared to Nikon) lens seemed favorable.
Initially, I was happy with the lens .. but not wowed.
Further use, it seemed that the photos just were not as sharp as I expected.
About a month ago, I took the lens out and did some tests for sharpness.
I used a tripod, set the focal length to 50, and varied the aperture to see results.
This is what I got.
The difference in sharpness when clamping down was remarkable.
But the issue is this: If I have to clamp the aperture down so much for sharpness, than whats the point in having the faster lens since I have to slow it down?
Yesterday, I did another set of tests against my favorite lens, my 35mm f1.8 prime.
First result was damning for the Sigma. So much so that I was ready to put it on Craigslist.
Nikon on the left, Sigma on the Right. These were *handheld*, in A mode both at f5.6
Later in the evening, I setup the tripod and tried comparing the Sigma against my Prime.
The results surprised me.
This time, Sigma on the left, Nikon on the right. I used Paint.net to save as jpg's, at 70% to make them reasonably sized. The sharpness differential is similar enough.
At f5.6
At f9
These results show me that the Sigma can be sharper than my prime --- in certain situations.
I suppose I still have variables unanswered ( original shots up top were only against itself on tripod, next set handheld, last set tripod. )
It almost seems like it might be an issue of focus (?)
I wanted something a faster than kit lens, with similar if not better focal distances.
Reviews on this budget (compared to Nikon) lens seemed favorable.
Initially, I was happy with the lens .. but not wowed.
Further use, it seemed that the photos just were not as sharp as I expected.
About a month ago, I took the lens out and did some tests for sharpness.
I used a tripod, set the focal length to 50, and varied the aperture to see results.
This is what I got.
The difference in sharpness when clamping down was remarkable.
But the issue is this: If I have to clamp the aperture down so much for sharpness, than whats the point in having the faster lens since I have to slow it down?
Yesterday, I did another set of tests against my favorite lens, my 35mm f1.8 prime.
First result was damning for the Sigma. So much so that I was ready to put it on Craigslist.
Nikon on the left, Sigma on the Right. These were *handheld*, in A mode both at f5.6
Later in the evening, I setup the tripod and tried comparing the Sigma against my Prime.
The results surprised me.
This time, Sigma on the left, Nikon on the right. I used Paint.net to save as jpg's, at 70% to make them reasonably sized. The sharpness differential is similar enough.
At f5.6
At f9
These results show me that the Sigma can be sharper than my prime --- in certain situations.
I suppose I still have variables unanswered ( original shots up top were only against itself on tripod, next set handheld, last set tripod. )
It almost seems like it might be an issue of focus (?)
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