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Showing results for tags 'sigma 100-400'.
I've been shooting with Sigma 100-400 for couple of months. As others have mentioned I find that this lens punches way above its price point in terms of IQ. Also due to its compact size and weight I find myself bringing this lens along far more often than I've ever done with a lens with 400mm reach. Today I decided to test the lens to try to answer a couple of questions I had about the lens: 1. I was finding some inconsistency in sharpness even when shooting on tripod. There's been speculation in various posts that this could be due to mechanical shutter. I wanted to test this out. 2. I also have the TC-1411 teleconverter, but have not been making much use as I was uncertain about its impact on image quality. I've seen several reviews that report little to no IQ degradation from its use so decided to test it out. To answer the first question I took 3 exposures using mechanical shutter and compared the results. I found wide variation in the results. I repeated the test 3 times with the same wide variation. The test was conducted on a tripod (top of the line Really Right Stuff) at 100 ISO with 12 second shutter delay shooting from indoors ( no wind or other impacts). I then repeated the test several times with electronic shutter. While there was some variability between shots the differences were minor. Based on this relatively simple test I'm satisfied that the speculation that mechanical shutter impacts image quality in a noticeable way is in fact correct. I will be using electronic shutter with this lens from now on. In order to answer the second question I took a series of 3 images at 400mm and then at 560mm focusing on a group of junction boxes on top of a building ( distance about 230 meters or 750 ft. I chose this subject because the boxes have numbers on them which helped with subsequent comparison between images. Also the texture on the wall surrounding the junction boxes offered a further reference point. From each set of images taken at 400m and 560mm I selected the best one (differences were minor based on use of electronic shutter). I then compared the image taken at 560mm with 200% magnification with the one taken at 400mm with 300% magnification. I used these settings as I figured it would "roughly" equalize the result between using lens with teleconverter versus doing a more aggressive (equivalent) crop in post. All images were shot at 100 ISO in the case of 400mm F6.3 & 1/125 and in case of 560mm at F9.0 & 1/60 Below I've attached the comparison between the two. I will share which is which in subsequent post but thought I'd share and get some initial reaction to the comparative difference.