I know that everyone is different when it comes to buying photography equipment. When writing these reviews, I try to take these different types of buyers into consideration. For example, some people rely purely on reviewer/community feedback while others like to see sample images with the exact gear that they will be using. In addition to those people, we have our pixel peepers and number crunchers. These individuals want to see results from complex tests along with samples zoomed in 500% to see the most minute details of an image. This part of the review is geared towards this group of buyers but this is by no means a very technical review. Unfortunately, the super technical reviews that you can find on other sites require equipment that I do not have access to and therefore I cannot provide that amount of detail to our readers. Even without this equipment, I wanted to try to give these types of buyers something to work with while at the same time keeping the other groups engaged. Here we go…
ISO 12233 Test
|From Sigma ISO 12233 Test Chart|
First off, let me say yes, I know the chart is supposed to fill the frame but this couldn’t happen for a few reasons. The first is the Sigma’s minimum focus distance is 33.5 inches which doesn’t sound like an issue but 33.5 inches is a pretty good distance. Because of this, I had to back off so much that the chart did not fill the frame. I could get a bigger chart but I haven’t needed one until now. If you click on the image above it will take you to a Picasa folder where you can view full sized JPEGs. There are sample images from F/1.4 through F/11.
Based on what I had seen from the images I’ve already taken, I was not surprised with the results from this test. At F/1.4, center sharpness is good and this continues to about three quarters of the frame. From there, things are soft to the corners which are noticeably soft. CA is present and like most lenses shot wide open on a FF sensor, vignetting is visible as well. Like most lenses, results improve as you stop down the aperture. By F/2.2 sharpness is up throughout most of the frame but the corners are still soft but CA is less prevalent. By F/4.5-F/5, sharpness is very good throughout the entire frame and CA is all but gone. Be sure to take a look at the JPEGs and make your own judgments.
OK, I want to say something before I get a million comments about this test. I know there are a bunch of different ways to go about performing this test and some even say it’s all BS, but I’ve had the good experience using Tim Jackson’s method in the past so that’s what I’ve decided to use. Take a look at his website if you want to get all of the information needed to perform this test.
I was more interested in putting the Sigma through this test than any other. Ever since it was released, the Sigma 50mm F/1.4 has had a reputation for front or back focusing issues. Front and back focusing is pretty self explanatory, but for those of you that have never heard of front/back focusing, here’s a quick rundown. Front focusing is when you set your focus point on a specific area but due to a miscommunication between the camera and the lens, the point of focus is actually in front of the intended area of focus. Back focus is the same thing, but in reverse. Many newer camera bodies have a micro adjustment (Canon’s terminology) feature which allows you to account for front/back focusing issues within the camera. Unfortunately for Sigma, there are a massive amount of complaints from customers experiencing focus issues with the Sigma 50mm F/1.4 which has caused some to have second thoughts about Sigma and their lineup of lenses.
I’m not sure if Sigma has fixed the issue or if I was just lucky and received a good copy, but the Sigma 85mm‘s focus seems to be spot on. Even at F/1.4, focus seems to be very accurate. Again, due to the Sigma‘s rather lengthy minimum focus distance, running this test was slightly difficult. But after performing the test several times with the same outcome, I’m confident in the results.
This test really isn’t meant to measure Chromatic Aberration (CA), but I think this test actually did a better job than the ISO chart. As you can see in the image above, CA is easily visible at F/1.4. Like you would expect, CA quickly drops off as you close down the aperture.
Lens flare is something that I never really think about when shooting. With a hood (which I always use) and all of the high tech coatings that are on most of today’s quality lenses, flare shouldn’t be a major problem and this holds true for the Sigma 85mm F/1.4. I really had to try to get any amount of flare from this lens and what I did get was nothing to write home about. I tried several times to force some flare into the shots and this was the best I could do. I’m not sure if that is a knock on my photographic skills or if that is praise for this lens. I’ll go with the latter.
- One issue that I have with this lens that I did not mention in the previous posts is the minimum focus distance. The Sigma 85mm F/1.4 has a minimum focus distance of 33.5 inches. This may not seem like a big deal but it’s almost twice the distance of its 50mm counterpart. This may just be a personal thing but I found myself being too close to focus on several occasions…probably my 50mm mindset. Also, this large minimum focus distance made performing these tests rather difficult. For example, the ISO chart and the focusing chart should fill the frame but it was impossible to get close enough to get the entire sheet in the frame. While the minimum focus distance may be annoying at first, it is most likely something you can learn to work with.
- AF accuracy is solid, no front of back focus issues.
- Flare? (In mafia style voice) Forget about it! Its almost impossible to get flare with this lens. Even with the hood off, I had to struggle to get any amount of flare.
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