If you find you've got front or back focus, come back and ask about remedies, such as dot tune, Reikan Focal or the USB dock. This is a "finer tune" picture, you should stagger yours at a greater angleĬharts shot at 45 degrees can show you in exact numbers how far forward or backward your center of focus is Do this test up close (for 18), and a little further away (for 35). This is not uncommon, and the reason the 7D has micro adjustment, and the reason that Sigma makes the USB dock (which I highly recommend BTW). If you notice that either the object that's forward or behind the target you're shooting is in focus instead of your target, you're getting either front or back focus. This will again give you a very narrow depth of field. Shoot the center object - use the camera from wide open to F4. Stagger some boxes or batteries as shown. This is extremely common with Sigma lenses - and no big deal.
If you find that you're not achieving focus (or know all this DOF stuff), then do the following: This will verify that your lens is capable of achieving focus, and takes your AF system out of the equation. You should find it easier to achieve focus at 18 than 35 when you do any of these tests.Īlso, try focusing using live view. Do these focus tests at close and far range. Of course, stationary objects are best as to eliminate any possible error. My suggestion is to first shoot at a higher aperture using only your center point focus, F4, F5.6, F8. You can see the focal plane travel from her eye to just over her ear! Note the top of the dog's head is blurry, as is her nose, as are her ears. If you're off just a little - or not using your center point focus - the camera will move focus forward or backward. Note the "stripe" of focused area (also called the focal plane because, that's what it is!), on the bedspread and draws at the same angle of the camera to the dog's eye.
#SIGMA 18 35 T6I REVIEW FULL#
With a full frame camera it's even more apparent. With a crop camera if you've been using a typical variable aperture lens, you've probably not experienced this. This could be one problem - and is a typical issue when people get a fast lens and are unfamiliar with DOF (depth of field).
Ok, first of all if you're shooting at F1.8, your plane of focus is going to be extremely narrow, thus exact focal point placement is incredibly critical. No, probably nothing at all wrong with your camera. There's nothing wrong with my camera – I have tested on multiple other lenses. I highly recommend the $50 for the dock to get the most out of this lens. I have no clue if there's anything actually wrong with my lense – or if there's a typical problem with this lense? Could I try calibrating it with a USB dock (that I don't own)? I'd probably have to focus on the nose to get the mouth in focus. Let's say I'm photographing a face, close-up at F1.8. When I focus it ends up focusing below my selected point. I'm liking the look and the feel, but I do have one problem with it: I've recently purchased Sigma's 18-35, 1.8 Art lense.
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