lucki

Sorry for the late reply. I'm in Melbourne and posted quite late at night. I understand where the advice was coming from now and can appreciate you were discrediting the test for my benefit, not to dismiss me out of hand. Andrew is right, the internet makes it easy to overlook things and I was mistaken when I perceived his response as criticism. I appreciate everyone's advice. Thanks for the follow-up Andrew, I could easily have made the mistake of stopping down after setting focus and my new humble tests confirm something was likely wrong with my method as the Sigma performed a lot better. I have posted links to them below. The high resolution files can be downloaded from a link on the side. Unfortunately it's way too hot and sunny here at the moment to shoot a brick wall (30-43 degrees celsius the last few weeks), so I grabbed a random newspaper instead. Please note these tests were with a standard Metabones Nikon to M43 adapter, not a speed booster, as I wanted to test the lens without additional glass. The adapter seems to cut a little light so wide open at F1.8 it is about as bright as the Voigtlander at F2 which is why the images are at slightly different apertures. Disclaimer: these tests are designed to help me make decisions about my kit because I have seen no comparisons with the Voigtlander 17.5mm. I hope they might be of use to others but they are not professional tests! Test 1 focus was set to the smaller black and white group photo http://i32.photobucket.com/albums/d7/lucki231/Test1Sigmaat18mmF18ISO400_zps9333702a.jpg~original http://i32.photobucket.com/albums/d7/lucki231/Test1Voigtlander175mmF2ISO400_zpsa0b08ecd.jpg~original Test 2 focus was set on the buckle of the bag http://s32.photobucket.com/user/lucki231/media/Test2Sigmaat18mmF18ISO800_zpsaea451e0.jpg.html http://s32.photobucket.com/user/lucki231/media/Test2Voigtlander175mmF2ISO800_zps1706c1d7.jpg.html Test 3 focus was set on the middle of the green and white cushion. An attempt to replicate my earlier test. It appears there was something off with the earlier one as the Sigma is a lot better here. http://i32.photobucket.com/albums/d7/lucki231/Test3Sigmaat18mmF18ISO400_zps99d8a5b5.jpg~original http://i32.photobucket.com/albums/d7/lucki231/Test3Voigtlander175mmF2ISO400_zps779a4cf9.jpg~original Hopefully these comparisons are of some benefit. Thanks for all the input.

Please also ignore the 1024 resolution image, there is a download link on the bottom right hand corner where you can access the full resolution version. Thanks again.

Thank you to the first responder. You are correct that the depth of field appears different for each lens. The Nokton seems to front focus whereas the Sigma back focuses, the actual depth of field being the same. I will test on a brick wall as you suggested. Regarding the second response, 'crap test' and 'clueless' are hardly necessary. I was asking a question based on my limited experience to get some advice from people with better knowledge about this lens. In fact, I came on this site because I previously respected the author and even paid $30 for his GH2 shooting guide. I won't be doing that again. Your overreaction is mean spirited and 'clueless'. I'm sure you can out-test me if you want to. I set focus correctly. And this is precisely my problem, I set focus on exactly the same point on the green and white cushion in both images. This is an issue I have been having repeatedly when comparing the lenses. Thanks to the first responder. My sigma seems has front focus problems, which can happen with a bad copy of the lens. This issue is all over the internet and the dealer I bought it from suggested it is causing the problems.

Hi, I was wondering whether anyone has had similar experiences to myself with this new lens from Sigma. Many people have referred to it as '3 primes in 1' but when I have tested it I have found it can be a bit soft compared to my better prime lenses. I have tested it on my GH2 with a Metabones Nikon to M43 Speed Booster and a Metabones Nikon to M43 basic adapter against my average to stronger primes. The following comparison illustrates what I mean. The Sigma image is at 18mm using a standard Nikon to M43 adapter, the Voigtlander at its fixed focal length of 17.5mm. Both ISO 400, F2, 1/50, NR off, AWB. They are pretty close but I feel the Voigtlander edges it. http://i32.photobucket.com/albums/d7/lucki231/Sigma18-35mmzoom_zps91755d8b.jpg~original http://i32.photobucket.com/albums/d7/lucki231/Voigtlander175mm_zps67a7484c.jpg~original What have other people's experiences been with the Sigma thus far? Can it really substitute for a set of good primes?