View Full Version : Focusing prob. w/ S2
1st of June 2007 (Fri), 07:57
One of the things I use my S2 for is taking pictures of model airplanes in flight (for a website I write for). My problem is that the pictures are often blurred. I've tried shooting in burst mode, but my thinking is that in burst mode it locks in the focus of the first shot (is that correct?), and these things are moving pretty darn fast. So I switched to single-shot mode but still with spotty results. At full zoom the planes fill anywhere from 80% to 5% of the frame, depending on their size and distance, and I have been shooting in program mode mostly but have recently tried aperature-priority wide open (I know I lose depth of field but I'm usually shooting at least 75-200 feet away, and wanted the faster shutter speed to reduce shake). Any tips? Is the S3 better at fast focusing?
1st of June 2007 (Fri), 18:48
My experience is thirty years with film of all formats and three months with digital. I have an A700 which I like a lot.
I've never done model aircraft photography but what you are trying is tricky to do with any camera in any price range. With a super fast digital SLR it would still be hard work, with a film SLR also hard work and with any point and shoot I think it is too difficult to consider.
There are three different problems. Subject motion, camera motion and focus. You are going in the right direction with wide aperture and short shutter speeds. But matching camera motion with subject motion is tricky, probably something that gets easier with practise, I don't think the camera makes much difference there.
Here is a thought. If the subject is between 75 and 200 feet away then so far as the camera is concerned it is nearly at infinity and there is no need to change focus when the subject moves from 75 feet to 100 feet for example, it is simply at the infinity end of the focusing scale. Possibly the camera tries to focus, by racking in and out, which takes time, but after hunting for and finding the plane the setting is always the same, infinity. In other words the camera, an obedient machine and not knowing any better, goes looking for focus when it need not do so. If it were to be focused at infinity and left there then 90% of the shots would be in focus and a lot of precious time can be saved by eliminating repeated focusing operations.
This may be worth a try. Set the camera in manual focus mode and focus on the most distant thing you can see and leave it there. This could make a major difference by shortening the delay between shutter release and exposure.
Auto focus is on every digital camera but it is the most tricky of the functions to automate. By comparison it is easy to automate exposure, everything about exposure can be analysed and predicted. Focus is not analysable in the same way. The focus is a matter of choice and the camera doesn't know what you are thinking.
There may be some advanced autofocus SLRs, like the Canon EOS models, that have predictive autofocus that can track things like model planes. You might try asking the same question over in the EOS SLR forum and see what they recommend.
1st of June 2007 (Fri), 20:05
Here's another idea. Sports photographers used to have the same problem following the action around the field. It is a problem with conventional SLRs and any closed viewfinder camera is usually less than 100% of the final image area. The problem this causes is due to loss of the information that the unaided eye is able to find by scanning across a wide area very quickly. The closed eyepiece type of viewfinder limits the view to the photographic frame with no information available outside of the frame. Everything going on outside the frame is unknown and that hinders the skills we have for co-ordinating eye and hand in anticipation of the motion of things. What is wanted is a wide view frame to permit rapid eye scanning and anticipation of motion, and, a pointing or aiming method to align the camera with the subject.
So one solution to the problem was to provide a special type of viewfinder for fast action that became known as a "sportsfinder". It has no lenses, it functions like a gun aiming sight, there is a front mark and a back mark and when they are lined up the camera is centered on the subject. Because there is no enclosure to block the view the eye is free to scan the subject and anticipate the positions of moving objects. This is much easier to understand from a picture, I've attached one from a Mamiya camera catalog. The camera lens is out of the frame at lower right. The photographer's eye would be at the upper left and observes the small rear sight and the front frame at the same time. The picture is a jpg attached.
Maybe you can find a way to add something like this to your S2?
1st of June 2007 (Fri), 20:31
1st of June 2007 (Fri), 20:49
well, there are a few things you could do in order to try to improve the quality...
first, use manual focus... if you're shooting flying planes, then set the focus to infinity, and leave it that way... you will gain a few miliseconds.
a huge step back with the s2 and s3, is that when you're literally taking the picture, both the lcd and the evf goes black... that's a darn pity, because it doesn't enable you to do a nice span, with the subject in sigth... this thing doesn't happen with a dSLR, so spanning would be a bit easier (not easy, it's a tecnique i think needs to be practiced).
Finally, the IS mode won't work miracles. I've been able to take sharp pictures of airborn planes, but those planes were about 500-600 meters away from me, so even going at 200 knots, it didn't seem that much.
i'd try to:
Set the aperture value, to let the camera take as much light as it can. This will help you to achieve faster shutter speed
try shooting up to iso100... you will gain again, a few ms
Keep the airplane in the evf for 2 secs, in order to "feel" how fast it's going, and then press the shutter release, and try your best to point to the plane.
cross your fingers, that might help :P
All joking aside, i think you should be able to get a few decent shots. ;)
2nd of June 2007 (Sat), 16:07
Thanks for your suggestions. As you figured out immediately, the EVF is pretty useless for this kind of photography - the first thing I did was make myself an gunsight-type optical viewfinder with an 8" length of 1/8" aluminum tubing clamped to an L-bracket that is screwed to the bottom of the camera. It looks silly but once I get it pointed to exactly the same spot as the lens, it works great. So following the plane is not difficult at all. As for setting to infinity, I thought that would work too, but my lens is 72mm (actual, not 35mm equivalent) at max zoom, which puts infinity about 300 feet away according to my tests. That's too far away to get any clarity. So I'm stuck with focusing.
I'm torn about opening wide to freeze motion vs. stopping down to gain depth of field. Today I shot some tests, and the ones that came out the best were shot at full point-and-shoot brainless auto! It chose a wide aperature, and while some were out of focus the ones that came out were quite nice. So maybe I've been going about this the wrong way. I'm so confused... Pics attached - top one is manual exposure, f6.3, 1/636; no detail, terrible. Bottom one is full-auto-everything, f4.5, 1/1000. Just what I'm looking for. Maybe I'm being too clever by half, as my British grandmother used to say!
2nd of June 2007 (Sat), 16:37
well, there's quite a difference there... it's pretty obvious...
the only thing that comes to mind, is that a 1/1000 shutter speed will eliminate virtually any chance of motion blur... of course, if you aim correctly, as you did.
haveing said that, 1/600 is pretty fast too, so with the appropiate spanning technique, you should be able to capture a image, with no motion blur whatsoever...
so, if you ask me, i think that the focus thing is just killing you. i don't think that's motion blur, i think that the first pic you posted is just out of focus.
2nd of June 2007 (Sat), 18:05
I'll agree with SaNdMaN - the prop's nicely blurred even in the second shot, so I think it's a focus problem. You want a slow enough shutter speed to blur the prop so it looks "real"; usually on the full-sized birds 1/250 is good. Try some shots with a typical model plane stationary (so it's easy to focus on) with the engine running and see what shutter speed gives you prop blur that appeals; you'll then be able to use Tv or M (carefully computing exposure beforehand) to catch the planes.
2nd of June 2007 (Sat), 22:38
Looking at these pics, I'm impressed by what the camera can do and with your DIY aiming system. It's clear from these shots that focus is important, more than I had allowed for so maybe the best direction to head in is towards rapid focusing cameras, perhaps the SLR types, and the lighter the better.
3rd of June 2007 (Sun), 00:07
Well thanks all. I think we have consensus - my S2 has trouble focusing under these conditions. Which, I have to say, is perfectly understandable. These are very very tough conditions. Notice this particular model is covered mostly in clear covering!
I have an opportunity to test a Panasonic Lumix FZ7 next weekend - it'll be interesting to see if it behaves better. If I could afford a dSLR I'd own one, but I just can't right now. I'll post back with the results. Thanks.
5th of June 2007 (Tue), 19:53
Someone asked for photos of my "gunsight" - here:
5th of June 2007 (Tue), 22:01
One thing I've had success with when photographing fast moving airplanes is using the LCD screen to aim, and holding the camera at arms length. That way, when I'm trying to pan with the plane, I can use both of my eyes to judge speed, distance, etc... I also try to use less zoom to have more room for error on getting the plane into the shot. Here's a couple of examples (both shot with a SONY video camera in photo mode, so please pardon the quality...it's all I had available):
1. F-14 taking off @ approx 200 MPH. Distance of approx 450'. FL 42mm, f/5.6, 1/500 sec.
2. Blue Angels F-18 during practice @ approx 650 MPH. Distance of approx 300 ft. FL 4.2mm, f/5.6, 1/500 sec.
The camera had a 10x optical zoom, and the first shot was full zoom, with the second shot full wide. I know these are not the best quality due to the 1 meg camera, but with higher MP cameras, you will have more ability to crop without loosing detail. Just my two cents.
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