11/24/2023 0 Comments Sigma 24 70 2.8 if ex dg![]() Sigma’s pro-spec 24-70mm f2.8 full-frame zoom lens is available in Canon, Nikon, Pentax, Sony and Sigma mounts, and was tested here in conjunction with a Nikon D700 (full-frame) body.The first thing to note about Sigma?s 24-70mm f2.8 lens is its considerably lower cost than other premium zooms. Sigma 24-70mm f/2.8 IF EX DG HSM review – MTF graph: These are good curves that show strong performances overall and only weaken at f/2.8 for all focal lengths. It isn’t perfect but it is a fine lens that is definitely worthy of consideration by anybody who is in the market for a pro-spec, full-frame standard zoom. It is also a pleasure to use and returns some excellent results. Overall, Sigma’s 24-70mm f/2.8 zoom is lighter, more compact and considerably less costly than Canon’s, Nikon’s and Sony’s equivalent zooms. Similarly, there is some distortion at all focal lengths but at no stage does the distortion become obtrusive. This is a shame given that the primary advantage of any fast lens is the ability to take advantage of low aperture numbers – but from f/4 right through to minimum aperture its MTF figures are above the critical 0.25 cycles-per-pixel threshold. Optically, the Sigma 24-70mm f/2.8 IF EX DG HSM lens is rather weak when used wide-open. The focused-distance window includes markings that indicate depth-of-field for the 24mm focal-length setting but there are no markings for other focal lengths. Sigma has provided just the right amount of resistance on the manual-focusing ring, but the zoom ring is a shade on the heavy side. It is important to note, however, that Sigma’s instruction sheet warns the lens can only be used in AF mode when mounted on camera bodies that support HSM-type ultrasonic drive motors. That said, the lens can also be manually adjusted at any time. Having the manual-focusing ring at finger-tip touch could be a liability were it not for the internal-focusing drive system, thanks to which the focusing ring remains stationary in AF mode. Sigma 24-70mm f/2.8 IF EX DG HSM review sample image Under other circumstances this change of grip might have left the lens feeling rather unbalanced but the Sigma’s compact dimensions largely avoid this problem. The zooming ring is wider and positioned to the rear, meaning that the left hand’s grip has to be shifted closer to the camera body. It nestles very comfortably in the hand with the manual-focusing ring falling naturally under the thumb and second finger. Nothing appears to have been sacrificed in terms of build quality – the Sigma’s matt-black zoom feels solid and looks at home on the front on a Nikon D700. The big question, therefore, is whether this less expensive lens is a true bargain or simply an inferior corner-cutting pretender. Whereas Canon, Nikon and Sony all pitch their 24-70mm f/2.8 zooms in the £1,400 to £1,500 RRP bracket, Sigma’s lens is just £900 by comparison – and that’s before any on-the-street price discounts. ![]() The first thing to note about Sigma’s 24-70mm f2.8 lens is its considerably lower cost than other premium zooms. Sigma’s pro-spec 24-70mm f2.8 full-frame zoom lens is available in Canon, Nikon, Pentax, Sony and Sigma mounts, and was tested here in conjunction with a Nikon D700 (full-frame) body. Ended up stumping up the extra cash for a Canon 24-70 f2.8 L which auto-focused perfectly and gave noticeably better image quality but at a pretty hefty extra price.Sigma 24-70mm f/2.8 IF EX DG HSM lens review In the end I got the supplier to agree that the lens was defective and got a refund. It's not that the lens cannot focus because I could get pin sharp focus in manual mode but I think it may be a general problem with this lens and autofocus as I have seen lots of forum posts describing similar experiences. After getting the second copy looked at by Sigma the problem was slightly reduced but still not completely resolved. In the end I sent it back and got another copy which unfortunately had much the same problem. I had problems similar to yours in that there was an inconsistent focal error over the zoom range such that if I corrected for 24 (I don't think you can do this on the 40D) it would give soft focus above 40 and if the subject distance changed this also threw things out. I tried to use it on a Canon 7D and 5D mk II but found much the same problems existed on both bodies. I had the Sigma 24-70 f/2.8 HSM and had all kinds of problems focusing with it.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |