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DPChallenge Forums >> Tips, Tricks, and Q&A >> Why is my focus always off?
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03/31/2005 11:14:54 AM · #1
The last few challenges I've gotten a lot of comments about my focus being slightly off. This is frustrating to me because one of the major reasons I switched to an SLR from a point and shoot is to be able to better control the focus. A good example is my stock photography picture
in which the closest part of the tulips still looks in focus to me.

For my cemetary pic I tried to be very careful about the focus. I used a tripod and a remote and through the lens my subject looked perfectly in focus. I turned off autofocus and moved the focus in and out, but decided the autofocus was right on. Even when I got it home and looked at it on the computer it looked okay to me (I used a large aperture so not all of the subject was in focus, but most of it was). But still I'm getting comments about the focus.

Is it my eyes? Lens? Something I'm doing during editing/resizing? I'm getting so frustrated that I'm thinking of switching back to my point and shoot. Does anyone have any tips for me?
03/31/2005 11:23:51 AM · #2
We don't know what you are doing in post processing, so any comments on your procedure at this point would be pure speculation.

Did you use a tripod when shooting Tulips in Love? What lens were you using? 1/25 sec is fairly slow for for a hand held shot for all but the steadiest of hands.
03/31/2005 11:26:42 AM · #3
I guess my question about post processing should be phrased as, what could I be doing to mess with the focus (aside from noise reduction or actually adjusting the focus, like by adding blur, which I did not do).
03/31/2005 11:31:23 AM · #4
noise reduction is a bluring effect. Put the camera on a tripod get enough light and take several test photos. In the flower case you might have been a bit too close for the lens, thus being out of its focus range. Could be camera shake, it the shutter speed was slow. Try an exposure at at least 125th and as close to f8 as you can get. Don't do any thing in photoshop and look at the image at about 200 to 400%. That way you will know it it is the camrea. Make sure the lens is clean.
03/31/2005 11:34:05 AM · #5
The shutter speed is definately one where a tripod should be used. I know when I got my D70, it took a lot of pictures/pratice to get a steady hand after moving up from a lightweight point and shot.

You may want to use the logic of a Tripod for anything less than 1/60th of a second and hand held over that.

You could also practice firing a few rounds of shots at the slower shutter speeds and work on your camera steadiness. I know when I fire shots at 1/25th, I can take 10 shots and only 2-3 are crystal clear while the remaining 7-8 have a slight softness or shake.

Edit:
You DSLR is also going to be much more sensitive ("tighter") on your focal point (than a P&S) so you may have to adjust where you AF to ensure a balance across the whole image. I know in my amatuer experience, this has been the case.

Message edited by author 2005-03-31 11:36:53.
03/31/2005 11:36:39 AM · #6
Originally posted by rmtm333:

You may want to use the logic of a Tripod for anything less than 1/60th of a second and hand held over that.



The lens focal length must be considered into the equation for this statement to ring true.
03/31/2005 11:38:22 AM · #7
Originally posted by nsbca7:

The lens focal length must be considered into the equation for this statement to ring true.


Very true...Good point.

How close where you shooting Saiphfire?
03/31/2005 11:43:26 AM · #8
Just a thought, most viewfinders have a built in diopter adjustment wheel.......maybe yours needs to be adjusted.
03/31/2005 11:45:45 AM · #9
It's out of focus cuz you're shooting at 1/20 second an dprobably handheld. It's probably IN focus, but due to camera movement it's blurred.

In general you should not be shooting slower than 1/focal length. So if you're shooting 50 mm, don't go slower than 1/50 second. for 200mm, don't go slower than 1/200 second. If you have IS, then there is more latitude.

03/31/2005 11:49:20 AM · #10
THere are several factors here...
-the shutter speed. If using a 55mm lens then you should keep the shutter speed above 1/60 sec. If a 300mm lens, then 1/300. slight camera shake will hurt sharpness.

the rebel can autofocus - what focus point is lit? I keep mine set to the center point, but in most of the auto modes the camera decided what the point of focus should be.

how physically cose are you to the subject? there is a minimum focus distance that you have to stay beyond.

is your lens or filter clean?

your f-stop will determine how much depth of field you have. The larger teh number the smaller the aperture and the more DOF you have, the more DOF you have the more of you pic will appear to be in focus. At large apertures the DOF can be millimeters! The canon 50m 1.8 at 1.8 has a DOF of just a few inches - so if you focus is not dead on the while pic looks out of focus.

Is your diopter on your viewfinder set for you? If this is off you cannot see if the focus is right or not.

Post processing - ALL digital images need sharpening to look good on a CRT/LCD. There are many many ways to sharpen a pic - and some depend on the subject matter in the pic - but try FILTERS>SHARPEN>UnSHARP Mask and try 100%, .9 and 1 for the tree setting (in PS anyway). It will help.

You could try manual focus...
perhaps the lens is bad. Not likely, but possible.

Message edited by author 2005-03-31 11:50:00.
03/31/2005 01:04:35 PM · #11
Originally posted by saiphfire:

The last few challenges I've gotten a lot of comments about my focus being slightly off.
...
For my cemetary pic I tried to be very careful about the focus. I used a tripod and a remote and through the lens my subject looked perfectly in focus. ... But still I'm getting comments about the focus.


I do not own the 300D but when shooting with friends that do I've noticed their images of similar scenes tend to be a bit "softer" focused than mine.

I believe that is by manufacturer design and puts control of focus rightly into the hands of the photographer rather than the camera.

At first glance you might think mine is better, but not true. Every digital camera has built-in computer programming controls that can do a lot of things with images before they are recorded to disk. That is what allows them to give you variable settings, focus "sharpness" among them.

My camera always has difficulty with images that have a lot of fine or granulated detail. They tend to come out artificially contrasty and unnatural looking. I have mine set to no focus adjustments but I believe the camera computer still tries to "help" me anyway.

You are better off applying USM in post processing to handle sharpness than letting the camera do it for you.
03/31/2005 08:16:54 PM · #12
Everyone seems to be talking camera shake, but I'm talking about BESIDES camera shake. I almost always have my tripod attached to the camera and use it for nearly all shots, long shutter speed or not. Uncharacteristically, I didn't use the tripod for the tulips, but I did use my beanbag which holds my camera very steady.

The distance (or lack thereof) with the tulips is a thought... but my cemetary picture, for instance, is not too close and I still had the same problem (I wish I could post it, but the challenge is still going on and I wanted to ask about this asap so I can use it in the current challenges).

Edit: By the way, I forgot to thank everyone for their comments and suggestions! Every once in a while I get a really nice picture and it feels so good, but I can't seem to consistently do it for the challenges and I'm trying to fix that.

Message edited by author 2005-03-31 20:20:58.
03/31/2005 08:28:30 PM · #13
...As odd as it sounds, I think the lighting of the tulip shot (and the warm filter) make it look softer than it is. I'd like to see the shot without the filter, with the white balance as accurate as possible. I think i could better judge the softness of it that way.
03/31/2005 08:33:51 PM · #14
Do you use USM at all in photoshop?

03/31/2005 08:36:39 PM · #15
I find it interesting that each of your challenge entry shots is ISO 400. Several of them also at fairly long shutter speeds. The combination of these settings along with low light and camera shake (which can still occur with a tripod) will make your images very soft. I really don't see any of your images as being out of focus so much as being extremely soft due to the previously mentioned reasons.

Also, if you are doing a lot of post-processing to bring a picture up to par (esp. making it lighter if it was underexposed) will add additional noise and fuzziness.
03/31/2005 09:02:03 PM · #16
Why not post the original un retouched photo so we can look at it. Then we could tell if if was the camera or post processing.
03/31/2005 11:16:12 PM · #17
What tripod? I have a couple of cheap ones...not really sturdy enough for my 300, but enough for my earlier cameras.

are you pushing the shutter (while on the tripod) or using a remote or the timer function? If you are pushing the button use the timer! (a remote is better, less waiting!)

What mode is the camera in (auto, sport, A, T, M??)
What parameter is set (default is parameter 1 - this can be changed and one thing that can be changed is in-camera sharpness. I could not in PS get the sharpness back that the camera could give me with param 1) many folks recomend as little in camera sharpening as possible, but i am not of that school as far as the Rebel is concerned.

What lens are you using? the same one each time or is the focus issue with many lenses? is the 'focus' light lighting up in the viewfinder to confirm that the camera has finished focusing?
04/01/2005 11:42:37 AM · #18
do you wear glasses? do you wear them when you are taking your photos? just curious... i know if i don't wear mine when taking a photo my pictures are sometimes blurry (i don't need my glasses all the time )...just a thought !
04/01/2005 11:58:08 AM · #19
First of all, thank you to everyone who has suggested the ps unsharp mask. It made a huge difference in my pet challenge picture.

Here's the original of the tulips picture. It was a bit dim so the white background was yellowish which I didn't like. That was one reason I applied the warm filter. (I actually wanted the background to be blueish to set off the tulips, but every time I tried to do that the tulips got a weird halo around them so I decided I wasn't skilled enough to do that yet, but that is another problem altogether.)
04/01/2005 12:25:43 PM · #20
I don't see any point of focus. You need to do a specific test for focus and pay attention to each step. Are you using auto focus? Like aprilldr said, if you wear glasses, you camera needs glasses. If you ar eusing auto foucs not a problem.
04/01/2005 12:31:53 PM · #21
Originally posted by saiphfire:

First of all, thank you to everyone who has suggested the ps unsharp mask. It made a huge difference in my pet challenge picture.

Here's the original of the tulips picture. It was a bit dim so the white background was yellowish which I didn't like. That was one reason I applied the warm filter. (I actually wanted the background to be blueish to set off the tulips, but every time I tried to do that the tulips got a weird halo around them so I decided I wasn't skilled enough to do that yet, but that is another problem altogether.)


I downloaded your original and just tried Image:Adjust:Autolevels in PS. Then applied a light USM. Got this - nearer what you were looking for colourwise?



Done at the original file size, cropped, resized and applying USM last (last is important), image might have been closer to your nice idea! [There is a very light halo effect that I think is caused only by applying the levels on the small size image - done on the full size image, then resized, it would look better]. Auto levels is often worth looking at quickly - the computer can do a good job or a really bad one, but worth checking until you are confident about playing around with them yourself!

Message edited by author 2005-04-01 12:36:44.
04/01/2005 01:05:34 PM · #22
Looks rather soft. Also it looks like you could use more light in the photo.
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