This is not a scientific test at all. I have been using my Sigma 85mm F1.4 with my Canon EOS 6D for a few years and is my default setup for my portrait shoots. My everyday/travel camera is an Olympus OM-D EM10 and recently purchased a Kamlan 50mm F1.1. The main differnece between the two are, the Kamlan lens is manual focus only whereas the Sigma has auto focus. Of course the Kamlan is a lot smaller and lighter. Because the Canon/Sigma combo is very heavy, I just do not want to carry them on vacation and various trips. Whereas the Olympus/Kamlan combo is hardly noticeable. I thought it would be a good idea to compare them for sharpness and bokeh. Lets start with size comparison. As you can see, the Canon/Sigma is much larger than the Olympus/Kamlan. Also from my experience, you don't want to carry the Canon/Sigma combo all day. It gives me a sore shoulder if I have to carry it for a whole day.
So lets start. Here is a photo from each combination. Both at the maximum aperture of each lens (I will only compare them at max aperture). With the Sigma lens the minimum focus distance is much longer than the Kamlan which limit the amount of background blur you can achieve with this subject. Also, I was shooting indoor at night hand held and had to bump the ISO to 1600 with the Canon to achieve blur free image. Whereas with the Olympus I was using ISO 400 because it has in body image stabilization (IBIS) and was able to shoot blur free image at 1/15s. In these two images I was trying to frame them the same but actually the Kamlan is a tighter crop.
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| Canon EOS 6D, Sigma 85mm F1.4 @ F1.4, ISO 1600, 1/80s |
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| Olympus OMD EM10, Kamlan 50mm F1.1 @ F1.1, ISO 400, 1/15s |
Background blur wise Kamlan achieved more blur, only because it can focus closer. When I shot at the minimum focus distance of the Kamlan, here is what I got. I was surprised the amount of background blur the Kamlan is quite decent. Very comparable to a 85mm F1.4 lens on a full frame body.
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| Olympus OMD EM10, Kamlan 50mm F1.1 @ F1.1, ISO 400, 1/15s at minimum focus distance |
How about sharpness? So here is the 100% crop of these images between the two. There is no doubt the Canon/Sigma combination is a lot sharper. There are a lot of details visible of the Russian doll and contrast is much higher. Canon/Sigma definitely win this.
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| Canon EOS 6D with Sigma 85mm F1.4 100% crop |
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| Olympus OM-D EM10 with Kamlan 50mm F1.1 100% crop |
What I was quite surprised to see was the level of noise between the two images. Since I was hand holding the cameras, I had to shoot at ISO 1600 with the Canon against ISO 400 with the Olympus. The Olympus image has less noise. That is a benefit of IBIS that is less known, but only for non moving subjects.
So in conclusion, Kamlan can achieve very good level of background blur although the sharpness is not at the same level. With IBIS, image noise can be lower than full frame (if the lens do not have IS).
At the end of the day the Kamlan 50mm F1.1 is not as sharp but fun still the same. I will carry on using it for day to day non critical photos. Sharpness is not the be all and end all of photography. I would highly recommend the Kamlan lens.
