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Thread: Underwater Exposure Settings

  1. #1
    Gerry's Avatar
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    Underwater Exposure Settings

    I would be interested in getting opinions as to what equipment/settings it took to get this shot:

    http://tinyurl.com/ydd5gt9

    Wouldn't there be an incredible amount of noise? What shutter/ISO speeds? I describe the shot as

    Quote:
    seagulls taking flight before a small coastal farm in Iceland
    and it is third from left in slideshow.


    Thx. for comments.

  2. #2
    arith's Avatar
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    Re: Exposure Settings

    Oh good a guessing game. Well they look a long ways away and are blurred and I don't really know how big a bird looks in a telephoto.

    I don't think it is at the hyperfocal distance so 300mm 1/60 f16 400 iso. If that is not the game I don't know.

  3. #3
    Gerry's Avatar
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    Re: Exposure Settings

    No, arith, it's not meant to be a guessing game since I don't know the answer either. I am struggling with exposure settings/noise in low-light shots, etc., and wondered how this kind of shot could be accomplished without noise. I guess noise would not necessarily show up in small sized web use or small, hi-res prints. Also, selective NR could have been used since the birds are blurry anyway. Also, where did the light come from in this shot?

    Now for my real quandary re: exposure settings: It seems my expensive calculators of aperture/depth of field that I recently bought are wildly inaccurate. In calculating for aperture with a shot of 60'-infinity w/40 mm, or 500'-infinity w/135-200 mm, all with 1.6 sensor, it gives me suggested aperture settings of 2. or 2.8, 4.0, etc. which produce shots extremely out of focus. Even the depth of field calculators on this site seem wrong. How does one accurately figure settings if this is so?
    Last edited by Gerry; 19th January 2010 at 06:36 PM.

  4. #4
    arith's Avatar
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    Re: Exposure Settings

    Sorry; I didn't know and are completely unfamiliar with expensive calculators. It would be a good game though.

  5. #5
    Moderator Dave Humphries's Avatar
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    Re: Exposure Settings

    I typed a big long answer here then hit Quote button (in a moment of stupidity) and lost it all

    Alas, it wasn't recoverable by forward or back buttons.

  6. #6
    Moderator Dave Humphries's Avatar
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    Re: Exposure Settings

    Quote Originally Posted by arith View Post
    It would be a good game though.
    Now there's an idea for a bit of fun:
    Post a picture (in a new thread) with EXIF blanked and give a few different shutter speed, aperture, focal length and ISO options, and ask people to make their choice.

    See how many get it right.

    I'm in a funny mood tonight

  7. #7

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    Re: Exposure Settings

    Hmmmm

    Looks like it was shot with a Canon 1ds-MKIII maybe about 1/60 f22 and iso 400.

    That's how it looks to me anyway!



    Actually I can't take credit for that much as I'd like to - I found the shooting information here http://blogs.nationalgeographic.com/...-prize-wi.html

    Pete

  8. #8
    Moderator Dave Humphries's Avatar
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    Re: Exposure Settings

    Looks like I'd be rubbish at Arith's competition idea

  9. #9
    arith's Avatar
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    Re: Exposure Settings

    Cor; only 105mm, crikey. Well I get 1 point for 1/60 and 1 point for 400 iso, and 1/2 point for f16 since it is only 1 stop out. I think; 1.4 x 16 yes that's right.

    Peter wins I come second again. cheers.

  10. #10
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    Re: Exposure Settings

    Quote Originally Posted by Dave Humphries View Post
    Now there's an idea for a bit of fun:
    Post a picture (in a new thread) with EXIF blanked and give a few different shutter speed, aperture, focal length and ISO options, and ask people to make their choice.

    See how many get it right.

    I'm in a funny mood tonight
    And I thought I was a camera nerd

  11. #11
    arith's Avatar
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    Re: Exposure Settings

    Yes; and I was thrown by the small lens on a full frame camera. One could then ask why f22 where f8 would get enough dof.

    Actually it could be made harder by giving images with all the clues such as dof and bright forground against a cloudy sky. Motion blur can give the speed away.

    It is also useful to have an idea of the exposure if only to set the camera up quicker; I think. Oh it is fun anyway.

  12. #12
    Gerry's Avatar
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    Re: Exposure Settings

    I'm glad you guys are having all this fun at my expense. I'm still waiting for Dave to re-type his lengthy and experienced reply to my original subject for this thread.

  13. #13
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    Re: Exposure Settings

    If you were given the same camera, same time of day, same exposure settings, do you think you could duplicate a given image?

  14. #14

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    Have a guess :)

    Re: Exposure Settings

    There's significant motion blur in the birds, so a relatively low shutterspeed, also, high ISO noise won't show much in images that size. There seems to be a strong light source off to the left too.

    Why not just eMail Ryan and ask him?

  15. #15
    arith's Avatar
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    Re: Exposure Settings

    400 iso isn't that bad and I'd think if properly exposed hard to detect noise. Noise really becomes an issue with underexposed bits and 800 or above iso. You can tell it is relatively bright.

    As for dof I use a rule of thumb to find the hyperfocal distance from a known point. My 28mm has hyperfocal distance 5.2 metres at f8. So rounding to 5 f4 gives 10 metres, f16 2.5 metres and everything else somewhere inbetween.

    A 56mm lens is 2x28 so has hyperfocal distance 4 times further approximately 20 metres and 112mm is 4x28 or 16 times further or 80 metres at f8.

    So a 105mm is going to be at least as good and those birds look further than 80 metres away meaning it could have been taken at f8 1/250 200 iso so I guess the blurring is deliberate.

  16. #16

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    Re: Underwater Exposure Settings

    More than likely it has been PP'd so who knows what it looked like straight out of the camera. I guess the full frame sensor helped a lot with the low light performance.

  17. #17
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    Re: Exposure Settings

    Quote Originally Posted by Gerry View Post
    It seems my expensive calculators of aperture/depth of field that I recently bought are wildly inaccurate. In calculating for aperture with a shot of 60'-infinity w/40 mm, or 500'-infinity w/135-200 mm, all with 1.6 sensor, it gives me suggested aperture settings of 2. or 2.8, 4.0, etc. which produce shots extremely out of focus. Even the depth of field calculators on this site seem wrong. How does one accurately figure settings if this is so?
    I guess the answer to my question is buried somewhere in Arith's response: One must just get to know your individual lenses and forget about trying to calculate for the exact depth of field settings for any particular shot. Correct? I recently bought these calculators, http://tinyurl.com/ybaqtzv, and found them wildly inaccurate at long distance shots where in-frame subjects were long-infinity. I'm not sure about shorter distances. I would appreciate comments as to whether of not I'm on the right track with this thinking. Thx.

  18. #18
    Moderator Donald's Avatar
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    Re: Exposure Settings

    Quote Originally Posted by Gerry View Post
    IOne must just get to know your individual lenses and forget about trying to calculate for the exact depth of field settings for any particular shot. Correct? I would appreciate comments as to whether of not I'm on the right track with this thinking.
    'Yes' is my answer to your question, although, clearly, you need to have an idea of what you're trying to achieve before you press the shutter. And that includes planning for DoF.

    I have to confess that the products that you refer to seem a but 'gimmicky' to me. I would say that you need to get out and shoot, shoot, shoot with the lens(es) you have and find out what they do at all settings.

    If you want to look at DoF calculators, play about with http://www.dofmaster.com/dofjs.html. If you would like to read an article entitled "Using Hyperfocal Distance to Ensure Maximum Depth of Field in Landscape Photography", go to http://photo.tutsplus.com/tutorials/...e-photography/. It offers a very accessible introduction to the topic. Of course there is also the tutorial on this site.

  19. #19
    arith's Avatar
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    Re: Exposure Settings

    I generally only use a guess; for me dof is mostly important for close up and regarding the hyperfocal distance this is the nearest in focus thing when focussed on infinity.

    A trick I use to get infinity to drop off is to place the infinity mark next to the far dof aperture setting on the camera but generally a formula I use for finding the hyperfocal distance depends on knowing the hyperfocal distance on one setting on my smallest lens.

    So if your smallest lens is Fmm and its hyperfocal distance is H metres at aperture A then at half that stop A/2 the hyperfocal distance is approximately twice as far.

    At twice the stop half as far.

    If for a different lens or zoom Gmm = cFmm the hyperfocal distance is c^2 x H.

    These are approximations based on the formula http://www.dofmaster.com/equations.html

    Of course it is better to know a few dof's for different zooms and work out beforehand just what is needed but dof can be approximated as a rough guide by d(H/(H+d)) ...d(H/(H-d)) where d is the distance of focusing.

    So my 28mm has hyperfocal length of 5.2 metres at f8 and I can't be bothered with hard sums so I round that down to 5 metres.

    A 250mm lens is roughly 9x28 and so very roughly the hyperfocal distance 81 x 5 or 400 metres at f8.

    So if you focus on something 200 metres away then we have 200(400/(400+200))...200(400/(400-200)) 130 to 400 metres.

    It is however very rough and requires a pen and paper but I could do this in my head when I was younger.

    Check herehttp://www.dofmaster.com/dofjs.html

  20. #20
    Moderator Dave Humphries's Avatar
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    Re: Exposure Settings

    Hi Gerry,

    I am a follower of Donald's "shoot, shoot, shoot" theorem

    I don't shoot landscapes often and when I do it usually still with a subject in shot which I (auto) focus on, then I just set what feels to be the highest f number I can get away with for a sensible shutter speed at the focal length I am using.

    If I am shooting something fairly close, but deep, I focus about 1/3 to 1/2 way "in" to the subject's 'depth' and just hope the aperture covers it. Assuming I want it all sharp that is

    All a bit hit and miss, eh? (That's me)
    My excuse is that I am concentrating on the subject, background, et al that will be in shot and not letting the technical aspects get in the way of creativity

    Gerry, if the "fun at your expense" made you , you wouldn't have liked my first reply, so I'll keep quiet

    My guess on the photo you linked was 1/125 - 1/350, ISO100 - 200, I also said it was a sunlit shot, so not needing high ISO and that some of the higher slopes were clipped, which, together with the reduction from a probable 4500+ width down to 1280, accounted for a lack of noise.

    The settings given for it above don't make a whole heap of sense to me either, but it is exactly the sort of thing I do; carefully set up for one shot and consider everything (as above), then turn around and take another dozen before I realise I am using inappropriate settings for the new view.

    Cheers,

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