Hi,
I’ve been using my Sigma 18-200 DC OS lens for a good 8 months or so now. It has been preety much the only lens I’ve had for my DSLR (the other being the Canon standard 18-55 EF-S which I haven’t used much). It has been pointed out by many photographers that my photos appear to be slightly on the blurry side. And I can see this too without any trouble. I can understand that sometimes photos are blury, that just happens, but this is a consistent problem that has occasionaly ruined entire sets of photos. I’ve attempted to improve, and spent a lot of time practicing technique and used faster shutter speeds than advised. But the problem still persists.
For example, this was taken at 1/800 (and is by no means the only photo like this):
http://www.jetphotos.net/viewreject_b.php?id=2141153
As you can probably see, that was never going to be accepted.
So I’ve decided that it’s probably not the technique that’s the problem (not entirely discounted, though). So my next question is, what about the equipment? After some thought and some discussion with some other amateur photogs, I have begun to question whether the Optical Stabalisation on my lens could be faulty. It seems to make logical sense, if the camera attempted to counteract camera movement but didnt move in the right direction, the effects could be detrimental. But, I know so very little about cameras. I was hoping that one of the educated folk from this forum could help me out.
So to sum up the long post, is it possible that the OS on my camera is causing blur rather than preventing it?
Thanks very much,
Dan Irvine.
By: Arabella-Cox - 4th October 2008 at 18:09
Old Shape, I shoot Jpeg. And I normally sharpen on CS3 with between 90 and 140 USM depending on the shot. Which I have been told is excessive despite having far more rejections for soft than oversharpen.
By: old shape - 4th October 2008 at 16:44
Yes, I do have a filter, however I believe the problems have been going on longer than I have had the filter. Although it is a possibility.
I can’t get out to do any tests this weekend as the weather is foul. I’ll try hopefully next weekend.
The picture on your initial link has been deleted by the host.
Post some in the thread please.
You didn’t state what sort of processing you are doing, and if you are shooting in RAW, Tiff or Jpeg…..all of which are “Soft” without some sort of sharpening. RAW is actually the softest, but can certainly end up as the sharpest.
By: Arabella-Cox - 3rd October 2008 at 20:28
Yes, I do have a filter, however I believe the problems have been going on longer than I have had the filter. Although it is a possibility.
I can’t get out to do any tests this weekend as the weather is foul. I’ll try hopefully next weekend.
By: vulcan558 - 2nd October 2008 at 23:03
Another question.
do you have a filter of any sort fitted to the front of the lens, this can have a poor effect also.
another reason when shooting at this angle is focus points use multi point this will help at this type of angle.
also this angle throws depth of field in to the subject with the airliner being a long subject a hundred feet long +.
pretty certain its settings and technique thats at issue as this lens thou on the avarage scale should produce better images . unless you have got a poor copy .
as ive said thou try a few different things , and the angle and speed of the subject . as been said the aircrat is heading at you at speed and not just on the horizontal panning faze its dropping on the vertical also.not sure if the aircraft is on rotation or finals but the effects are pretty much the same.
By: Arabella-Cox - 2nd October 2008 at 21:33
Hi tenthije,
My camera is a 400D. I hope it’s not the camera, as I don’t plan on replacing that anytime soon.
Thanks.
By: tenthije - 2nd October 2008 at 21:04
I’ve had much the same problem for a very long time with my previous Canon 10D. I am fairly certain it has a depth of field problem. This is actually a well known problem for the 10D. The camera was perfect for side-on shots, even with low speed panning. For anything at an angle I would always have part of the plane slighly out of focus. Similar to the nose of your 757 shot.
At one point I even sent the lense back for a check-up, as I was under the mistaken impression the lense was to blame. The lense got a clean bill of health, but the problem persisted. So either it was a problem with my shooting technique, or with the body.
While I never tried to get the 10D diagnosed (the price quoted for the diagnosis alone made it beyond economical), I know it must have been the camera. After I got a new camera the problem went away. So I do not think my shooting technique was to blame.
At the end of the day your camera is a piece of precision engineering. Anything can break.
What camera have you got?
By: Arabella-Cox - 2nd October 2008 at 17:58
Hi Vulcan,
by “giving the OS system time to start up” do you mean half pressing the shutter? Because I always do that when shooting.
The AF is a potential problem, and I think in some of my shots I’ve seen that might be true. However the shot I’ve linked in the initial post is the common problem, and that (to me) is clearly blur rather than focus.
I will try and get out at the weekend (wx permiting) and practice taking shots with OS on and off. If the shots appear significantly less blury in the non-OS shots I think I may have found the root of my problem.
I’ve checked the warranty, and the lens is covered for 1 years free repairs for manufacturing faults. So if it is the problem, hopefully the guys at sigma will be able to deal with it.
By: vulcan558 - 2nd October 2008 at 02:17
Yes, at those shutter speeds of 1/800th, you really do not need to use OS.
try shooting flying shots like the example pic you posted without the OS on.
Common problem is that many do not give the OS system time to start up and settle and do its job.
the other problem with this lens would be the Auto focus speed . the hardest thing for the AF is when the subject is heading towards you at speed, as the distance from the subject is changeing all the time and at speed.
you have to ask yourself can the AF keep up with ther ever changeing distance and speed of the subject and the shutter speed high enough to freeze it at that precise moment.
Also cropping the image to much can have effects like this when the image is cropped and saved at the wrong aspect ratio.
Sign In
October 1, 2008 at 8:24 pm