Sigma 18 35 1.8 pentax9/25/2023 ![]() Other APS-C users have posted information in that group also, do a search. If you want to see what you are getting with the Sigma, I've uploaded some 100% crops into the Great Astro Lens test thread over in the Astrophotography group (post #64) The Great Astro Lens Test - Astrophotography. For nightscapes, the Sigma 18-35 is better, obviously faster, but also better corner star shapes at wider apertures. For general day use, I can't fault it, cracking! Much better than DA limited options. The centre is good from f2.8 so it is usable depending how critical the corners are for you. I have some star 100% crops of the corner and centre in my gallery (also linked from the lens review I posted) but to summarise with respect to nightscapes, there is some elongation of stars in the corner at 11 mm and the star shapes in the corners at the 18 mm end are not perfect so it needs to be stopped down. I currently have the 12-24 F/4 and the old 16-50 DA* and I'm looking for something more modern.Very happy with it. Thanks, are you happy with the 11-18 DA*? I am planning to get the sigma for night scape and astrophotography. Even with the 1.5 crop from the KP should be nice enough for astro. I think the quality of that is pretty good - up there with the. All those 16-50, 11-18 are f2.8 and you need to stop down them.I have the irix on my wishlist. GlennH 17 1.9k 1 6:28PM Like 0 Can't help you with the Sigmas - I have the Tamron 17-50mm (non-VC) sitting on a 60D. For wide field I think there is nothing at all. They have *85mm f1.4 and *50mm f1.4 need to be stoped down to get good results, but then I don't see a reason to pay so much if they starting to be good from f2.8. I would be happy to spend my money for something good for astro(fast and no aberrations) from Pentax. I'm using Irix 15mm f2.4 and Rokinon 24mm f1.4 and Sigma 18-35, but on FF it usable from 24mm(very small crop needed). All those 16-50, 11-18 are f2.8 and you need to stop down them. I'm waiting for clear sky without clouds and moon. Now I'm going to buy again 21mm f1.4 from Irix, with 1st copy I had a bed luck. ![]() Very flat field, nice star shapes, only CA is makeing a bit of problem and slow f-number. I also own Takumar 200mm F4 in M42 mount. Rokinon 24mmf1.4 usable from f2.5, probably not best copy. Not the fastest but fast enough and on FF it's wide, maybe even too wide Irix 15mmf2.4 is really good lens for astro. I currently have the 12-24 F/4 and the old 16-50 DA* and I'm looking for something more modern. I was eyeing the f/1.8 for the extra stop of light. I don't want to carry both lenses.Yes, the list of modern glass is limited, which lens are you currently using for astrophotography? I have the 12-24 mm f/4 and the old 16-50 SMD lens. I have a couple major trips to foreign countriea coming up. The fact that the kit lens is water resistant is a plus. I haven't printed any large canvas prints from the 18-135 and am worried the quality may be subpar. ![]() I've noticed that with new lenses, it takes some time to adapt and am wondering if I'm just in the adaption phase. Even though I mainly photograph my family as well as landscapes, I'm missing the 1.8 f-stop and also missing the incredible sharpness of the Sigma lens. With the 18-135 and K-70 in hand, I'm feeling very mixed. It delivers excellent results wide-open, which sets the bar high for future zooms faster than F1.8, should they be released. To sum things up, Sigma's optical engineers have simply done a fanstastic job with the 18-35mm. I was hoping the improved low-light capabilites of the K-70 matched with in-camera correction should yield great photographs with a much lighter kit. Neither the Sigma nor the Limited zooms suffered such levels of purple fringing. ![]() I've been feeling that the lens combo is too heavy for my travels, so I recently purchased a K-70 along with an 18-135 kit. I know raw processing is superior, but the storage space and time just became too overwhelming for me. Note that I don't use RAW, but I use in-camera jpg. I've taken superb photos with this combo for much of my travels and my walls are covered with photos from this combo - typically printed out at 20"x30" and 24"x36". I've been a K-01 user and have taken many lovely photos with the Sigma 18-35 1.8.
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