In the fourth sample we've zoomed in to 35mm and placed the sun just outside the frame. The lens does particularly well here at maintaining contrast and shadow detail. Add to that the lens is sharper even than the work horse Nikon DX 35 mm 1.8...and you have a combination that will meet or beat the best from current full frames. Overall though, this level of chromatic aberration is impressively low, especially considering that we're looking at an ultra-fast zoom. It's no worse than we'd expect to see from fast primes, either. Flare

Sigma, 18-35, 1.8, DC, HSM, Art, Canon EF - HDEW CAMERAS

However, we believe most potential buyers for this lens will be demanding users - either serious enthusiasts or professional photographers. And while we think that they'll be delighted with the image quality the lens delivers when properly focused, they won't generally find this kind of hit-and-miss focusing at F1.8 very acceptable; the lens just doesn't reliably deliver usable images every time. This doesn't mean that there's no point in buying the lens at all - its outright image quality at normal working apertures is reason enough to get one - but it does mean that we'd recommend testing before you buy, if at all possible. Of course we've only used the Canon mount version of the lens - it's possible other versions may work better. Specific image quality issues I certainly wouldn’t recommend buying this lens if you only have a full frame body, obviously, but if you happened to also have a full frame body and didn’t have a 35mm prime this might prove a useful bonus. The R5 is effectively cropping the image for you. That’s more convenient than how the Canon 5D Mark IV functions, but the net result is still a low resolution image (18 megapixels instead of 45, the native resolution of the R5 sensor). This would give a 13-25mm F1.3, which, when mounted on a Four Thirds sensor would be equivalent to a 26-50mm F2.56 lens on full frame. From a qualitative perspective, there is little difference in image quality between 5.1K and 8K when downsampled to 4K. To demonstrate, below is some “4K Crop” test footage using the Sigma 18-35mm f/1.8 on the EOS R5. Sample 4K Crop footage using the Sigma 18-35mm f/1.8 on the Canon EOS R5The lens is available for both Canon and Nikon cameras, but there are two different versions of this lens (one for each brand and mount) so it is important that you ask for and choose the right version when bying the lens. Because an f1.8 APCS lens on an APSC sensor DOES gather the same total amount light as a f2.8 FF lens on a full frame. The APSC lens focuses all that light on a smaller circle, the FF lens focuses it on a larger one. But they both gather about the same number of photons in the same time. After reading many posts about 70D and Sigma 18-35mm having incosistent results I got disappointed, cause I also wanted to buy this lens to my 70D. Though I am not resident of Turkey, but I reside so I am also bonded to their rules. Here shops don't allow to test the lens before you buy. Fortunately there is demo item to test, but still not in all shops. As for sharpness. Hard to put in words. It's like you discovered what 24 mp can really do for the first time. Because you can open the lens to 1.8 you can literally have any dof and any bokeh you want. And low light: better than any dx prime and also flexible because of the zoom.

Sigma 18-35mm F1.8 DC HSM A Canon mount lens review: fixed Sigma 18-35mm F1.8 DC HSM A Canon mount lens review: fixed

Most people changing formats from APS-C to full-frame are likely to find themselves buying 24- or 28-70mm F2.8 zooms, as such a lens makes it easy to access the larger format's low-light and shallow depth-of-field capabilities. The key to understanding the Sigma 18-35mm F1.8 is to realize that it gives the same control over depth-of-field as a 28-50mm F2.8 would on a full-frame camera - it also allows you to shoot at wider apertures in any given situation, effectively cancelling out the greater low-light ability that a larger sensor would otherwise give. And, especially if you own a high-end APS-C camera, that can help to reduce some of the motivation for moving to full-frame. The Sigma 35mm F1.4 DG HSM impressed us hugely when we reviewed it at the end of last year, and is probably the sharpest 35mm F1.4 prime on the market. When tested on the same camera, the zoom may be just fractionally less sharp at large apertures, but you probably wouldn't see any difference in real world shooting. The zoom also has slightly higher vignetting and distortion, but lower chromatic aberration. From this data, you'd be hard pushed to see any meaningful differences between the two in side-by-side shooting. Remember this is the 18-35mm's weakest focal length. Compared to Tamron 24-70mm F2.8 Di VC USD The lens is impressively sharp at 1.8 WHEN IT FOCUS CORRECTLY! I spent about 2hrs yesterday playing with the micro adjustments and i still cant get it right. Focus is pretty accurate until you try focusing on something that is about 10ft and behond.

Studio Tests

What makes a standard lens ideal for you? Certain important qualities are required, such as fast maximum aperture, versatility for snap shots, portraiture and indoor photography plus a good combination of a wide range of focal lengths in a compact design. SIGMA 18-35mm F1.8 DC HSM is the first zoom lens ever to achieve a maximum aperture of f1.8 throughout the zoom range. It is a wide aperture, standard zoom-lens for digital single lens reflex camera´s with APS-C size sensor´s. *1The lens has a focal range equivalent to 27mm - 52.5mm in a 35mm format and it can cover the angles of view of multiple fixed focal length lenses. This wide aperture, standard zoom lens enables the photographer to expand creative possibilities on any occasion. The other take-home message here is that, while our copy of the lens showed a tendency towards focusing in front of subject (and therefore required positive microadjust values), the correction needed at each setting was different. So using a global in-camera microadjust value would necessarily be a compromise - setting a value to correct any given focal length and subject distance could throw off the focus at other settings. We observed this in practice using the Canon EOS 7D's microadjust feature - it could only be set to give optimal focusing at one given focal length and subject distance. Are we looking too closely? When I saw the above, I changed the setting on my Nikon D800E to switch to DX crop mode when the lens was mounted on it. Autofocus Performance and Accuracy On older DSLRs like the full-frame Canon 5D Mark IV, you can see what’s happening (see below). Images contain massive amounts of vignette. Once cropped in post, the image then has the same field of view as a 27-53mm full-frame lens. Sigma 18-35mm f/1.8 on the Canon 5D Mark IV

Sigma 18-35mm f/1,8 DC HSM Art Review - Lensora Sigma 18-35mm f/1,8 DC HSM Art Review - Lensora

What makes a standard lens ideal for you? Certain important qualities are required, such as fast maximum aperture, versatility for snap shots, portraiture and indoor photography plus a good combination of a wide range of focal lengths in a compact design. SIGMA 18-35mm F1.8 DC HSM is the first zoom lens ever to achieve a maximum aperture of f1.8 throughout the zoom range. It is a wide aperture, standard zoom-lens for digital single lens reflex camera’s with APS-C size sensor’s. *1The lens has a focal range equivalent to 27mm – 52.5mm in a 35mm format and it can cover the angles of view of multiple fixed focal length lenses. This wide aperture, standard zoom lens enables the photographer to expand creative possibilities on any occasion.Why does dpreview perpetuate the myth that an f1.8 lens used on APSC sensors has the same light gathering power as an f2.8 lens on full frame? At the same ISO (or ASA for film ) and lighting the shutter speed and aperture ( f1.8 in this case) will be identical for correct exposure on APSC, full frame, or any other format. This is basic science of optics. Lateral chromatic aberration is pretty low. The graphs indicate a little green/magenta fringing at wideangle, and moderately strong blue/yellow fringing in the middle of the range (note though that this tends to be visually less intrusive). At the long end, chromatic aberration is essentially nonexistent. Even without being able to use the Sigma with the OVF, i would STILL BUY this lens. There no other option on the market.