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Thread: New image

  1. #1
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    New image

    After reading everyone's advice and comments I went out and took a bunch more shots. Unfortunately I did not take any below an ISO of 800 ( thought I had, but did not) I did try a bunch of different apertures. Below is a link to one of the better shots. The shot has all the data left in it so you can see the shot details. Basically 70-200F4-L lens, Rebel T2i body, F-32, ISO 800, Exposure 1/15 sec, 200mm focal length. Hand held, af on, is on. Focused on tall pine tree. No processing done at all. RAW image straight from camera, converted to jpeg and uploaded through lightroom. Tree looks a bit bury to me. Also surprised at th amount of noise on a close zoom. Any thought are more than welcome. Thanks in advance!

    https://picasaweb.google.com/lh/phot...eat=directlink
    Last edited by NorthWoods Bill; 02-14-2012 at 11:10 AM.

  2. #2
    Moderator Steve U's Avatar
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    Welcome Bill, 1/15 sec is to slow to handhold and F 32 makes it even harder, probably an F5.6 or F8 aperature would have worked better and bumped the exposure speed up a bit so you can hand hold. Most of us will get a blurry image at anything slower than 1/100, even if you have IS not every image will stay sharp below 1/60.
    The pine tree in the middle isn't pleasing composition and you have a dead or bare sappling coming up from the foreground.
    There are long shadows on the ground it would have been interesting to stand in fronmt of the trees and shoot back topwards the sun, silhouetting the tree and getting some golden light. The rule of thirds for your points of interest make a more pleasing composition.
    If you copy the BB code from Picasa and paste it between these codes you will see your on the screen, rather than just the link. [img]your BBcode[/img]
    The main thing is just keep taking photos Bill.
    Keep posting.
    Steve U
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  3. #3
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    Sorry, should have pointed out that I was not going for composition. That hill is out behind work, I was more just looking for the technical aspect. I will reshoot today at F5.6 and F8 and ISO on auto. Should I limit the top end of the ISO or just trust the camera do to its job?

  4. #4
    Administrator Sean Setters's Avatar
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    Bill-

    Steve's right on with what I was thinking. I'd suggest aperture priority set to f/5.6, ISO 100 (or 200). Unless you absolutely need it, I'd avoid apertures over f/8 because of the effects of DLA (explained below). I've never used Auto ISO because ISO is something I always want to set manually depending on the amount of noise I'm willing to put up with in a given situation. Considering you're shooting snow during the day, lack of light should not be a problem for you.

    From Bryan Carnathan:

    "DLA (Diffraction Limited Aperture) is the result of a mathematical formula that approximates the aperture where diffraction begins to visibly affect image sharpness at the pixel level. Diffraction at the DLA is only barely visible when viewed at full-size (100%, 1 pixel = 1 pixel) on a display or output to a very large print. As sensor pixel density increases, the narrowest aperture we can use to get perfectly pixel sharp images gets wider."

    The DLA point for a T2i is approximately f/6.8, meaning using apertures above that can result in a visible loss of sharpness.


  5. #5
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    OK, so now I am beginning to understand it more. I will retake some shots at lunch time and upload them tonight following the above advice. Thanks!

  6. #6
    Senior Member clemmb's Avatar
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    Quote Originally Posted by Sean Setters View Post
    I'd suggest aperture priority set to f/5.6, ISO 100 (or 200).

    I agree with Sean, however, shooting with so much white, snow, the aperture priority may cause under exposure. Check your histogram and dial in a +1/3 or 2/3 compensation.
    Mark

  7. #7
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    @Bill I use that body/lens combo a lot. I didn't even know it could go to f/32! While Sean suggests not going beyond f/6.8 I've been comfortable with results as far as f/10 or so. The lens isn't as sharp as an f/200 f/2 so the diffraction effects don't show up quite as noticeably right at f/6.8.

    The only reason to stop down to f/32 would be to keep everything in-focus from very close to very far away. You photo above is all mid-far distance. You could autofocus on some of the scrub about halfway up the hill then click the DoF preview button to ensure the tree is in-focus. Let's saw you went from f/32 to f/8 then you have 16x more light to work with. So with that we could bring the shutter speed from 1/15 to 1/60 (which will be sharp with the IS on that lens) and the ISO could drop from 800 to 200 - a very reasonable place to be with that sensor.

  8. #8
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    Quote Originally Posted by clemmb View Post
    I agree with Sean, however, shooting with so much white, snow, the aperture priority may cause under exposure. Check your histogram and dial in a +1/3 or 2/3 compensation.
    Baby steps... Let's get the trinity of f/stop, exposure, and ISO first.

  9. #9
    Super Moderator Kayaker72's Avatar
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    Bill,

    Welcome to the forums. You have some beautiful country up there in Lancaster. I am looking forward to the photos.

    My first suggestion would be to pick up a copy of "Understanding Exposure" 3rd Ed by Bryan Peterson. It is $12-$16 right now on Amazon. I know several people here have read and use it, including myself (it is on my coffee table right now).

    Second, some rules of thumb that I keep having to remind myself of:
    1. To get a sharp hand held image your shutter speed needs to be faster than 1/(full frame equivalent focal length). In otherwords, on your shot above, 200 mm on a 1.6 crop body has the full frame equivalent focal length of 320 mm (1.6 x 200). So, without IS, you would need to have a shutter speed of 1/320 or faster to get a sharp hand held shot. But you have 4-stop IS. You may already know, but a "stop" is a doubling of light. So, for 4 stop IS should let you get a sharp image at 1/20th of a second (1/320 to 1/160 to 1/80 to 1/40 to 1/20). My experience is that you actually get 3-4 stops of IS, so at 200 mm you need to be faster than 1/20-1/40 to expect sharp images.
    2. This was covered above, but image quality tends to decrease with narrower apertures. Most lenses have a "sweet spot" for aperture. Reviewing Bryan's ISO 12233 charts would help identify the sweet spot for your lens. Typically, the sweet spot is somewhere around f/5.6 to f/8. This is where you lens is likely sharpest, but, as you'll read, you will often shoot at different apertures for "creative" reasons.

    Finally, I'd recommend something easy, but hopefully telling. Pick a stationary target in plenty of light that has a good amount of detail (I typically use a magazine page or a box with different font sized lettering). Adjust ISO to get proper exposure (or use Auto ISO) and shoot at 1/500 to 1/1000 and f/5.6 or f/8. If these aren't tack sharp, you may have an issue with your camera or lens. I'd also play around varying shutter speed and aperture (mostly aperture) to evaluate the results.

    Keep shooting and keep posting....

    Thanks,
    Brant
    Last edited by Kayaker72; 02-14-2012 at 01:07 PM.

  10. #10
    Senior Member conropl's Avatar
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    There are only a few instances that I would shoot at f/32, and if I did I would expect the shots to be soft. There are diffraction problems at small apertures. Usually f/8-f/11 are ideal ranges to get good depth of field (DOF) and sharpness for most lenses. There are times when I want more DOF because I have something interesting that is close in the foreground, but my main subject is at infinity... in this case I would push to f/18. However, much beyond that and the shot starts get noticeably soft (f/22 to me starts getting unacceptable and is a little better or worse depending on the lens). The exception may be macro where you may want to push it to get more DOF, but you would be using an exceptional lens that is better designed to go to f/22 and it would need to be on a tripod (and it is still not as sharp).

    Also as a general rule, shooting at wide open apertures does not usually provide the sharpest images either. For most lenses, shooting one full stop above the maximum aperture would increase the sharpness noticeably. I am not sure about your lens... it is a very good lens and maybe pretty good wide open. However, there needs to be a balance approach here as well. That is, the more open your aperture, the less the DOF is, but that is what separates your subject from the clutter of the back ground which can make for a more pleasing shot many times.

    Steve is also correct, hand holding at 1/15 sec exposure is getting dicey. Can it be done... yes, but your keeper rate is going to be miserable and you won't know it until you are looking on your computer (that little LCD screen lies
    ). At those exposures, you should be on a tripod. IS is good, but it is not the cure all, and it does not take care of motion blur. For example, your tree would be very soft if there was any kind of light breeze at all. IS works to help take out your movement not the environmental factors.

    As for limiting the top end of the ISO: Limit the top end of your ISO... high ISO = Noise, keep it as low as you can to get the shot you want with the exposure optimized to remove any motion blur and the aperture optimized for DOF concerns. To tell the truth, I never use auto-ISO, I set it myself so I can get the best picture. There are exceptions such as sport shooting where you want to maintain a certain shutter speed in changing light conditions outside. Your comment: "... just trust the camera to do its job". I do not trust the camera to do its job... I never use "P" mode (contrary to a recent youtube video posted here, it does not stand for professional). You need to be in control of your exposure as much as you feel comfortable, and as the experience level goes up, then you start taking more control and your shots will start coming out more like what you have pictured in your head.


    Sorry for getting long winded
    Last edited by conropl; 02-14-2012 at 01:36 PM.
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