Pre foucusing a shot?

Discussion in 'Beyond the Basics' started by Happy Hour, Jan 24, 2008.

  1. Happy Hour

    Happy Hour TPF Noob!

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    So I was reading understanding exposure for the 4th time today and came across the section where he talks about pre setting the focus on your lens for a shot. now I see the numbers on the lens but not quiet understanding how it works. on my wide angle 28mm the largest is 10FT so if i'm trying to capture a huge landscape, and want everything in focus. How do I know what to set it to? He didn't go into very much detail about it in the book and I can't seem to find much on the web about it. anyone have any insight about this?
     
  2. Sideburns

    Sideburns TPF Noob!

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    Well, you close the aperture down as he explains to the "storytelling apertures".
    I think on his 28mm, he usually focused about 2.5ft away or something like that? Try a few and see what you like.
     
  3. Happy Hour

    Happy Hour TPF Noob!

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    i'd love to try a few but Happy Hour is cameraless:grumpy: For another day!so it will have to wait, but I just didn't get that whole concept. I mean do you actually focus or just look at the distance markings and set it to a certain setting? It confused me a little. You say set it at 2.5 FT but wouldn't that limit my focus range to 2.5 ft. Or am i missing something? like some kinda calculation? like aperture/distance type thing? Maybe I'm talking out my Arse! I figured If I am presetting focus i would focus to infinity for everything to be in focus. I know I'm way over thinking this, thus my confusion. Someone give me a kick in the head to set me right again?
     
  4. JerryPH

    JerryPH No longer a newbie, moving up!

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    Hyperfocal... this is where you focus on something ~1/2 way to where you want, and play with aperture for very deep DOF.

    Hard to understand until you've done it a few times. In the winter, indoors its harder... outside with lots of room it becomes more evident and easier to catch the concept. Once you get it, its like riding a bike, and always there for you.

    BTW, I hope you get your camera back soon. :)
     
  5. Happy Hour

    Happy Hour TPF Noob!

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    Thanks Jerry! My A100 wasn't shooting right since the day I bought it. At first I thought it was me but the more I used it the worse my pics got. So we did a comparison test and it was just a lemon. the good out of it all Is I upgraded to the A700 (which is what I wanted in the first place,but they were on back order) Anyway The reason I was interested in this was I was taking some great shots of the lakeshore in sunset with the waves frozen on the shore but with my aperture wide open either it would focus on the distance or focus on the rocks close to me but No matter what I did I could not get a entire landscape all in focus. (at least the way I wanted) So I guess i'll just wait till tomorrow when i have a Digital camera 2 play with and see for my self. thanks for everything!
     
  6. jlykins

    jlykins TPF Noob!

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    I may be wrong here, but I think you have to use manual focus to get the story telling photo's right. I have been pondering the same question as you, but since it's like 3 degree's here right now I haven't been able to get out and play around with this type of shot.
     
  7. Happy Hour

    Happy Hour TPF Noob!

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    I Know you have to use manual focus, hence Pre focusing. it's been -32 wind chills here the past few days now. I was on my home from the museum and it just happened to be 2 sun set so i couldn't resist, I pulled off Lake shore drive on the shoulder and ran down 2 the beach and snapped a few off real quick. But the results were not exactly what I wanted, still I got 1 decent one out of 5
     
  8. Sideburns

    Sideburns TPF Noob!

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    Do you understand depth of field properly?
    Especially with a wide angle lens such as the 28mm...depth of field is huge when you stop down. This renders so much of the scene in focus it almost doesn't matter. However, basically you aren't looking through the viewfinder to focus...only to compose. Then you set your focus based on the distance markings. The DOF will do the rest.
     
  9. Happy Hour

    Happy Hour TPF Noob!

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    I the landscape shots I usually take have a large DOF But there is always some part that is less in focus than others and shooting the Chicago skyline I want the entire pic in perfect focus. It's not that I don't know DOF I just never tried the prefocusing B4.And wanted to know more details on how to properly use it. The way it was described in the book he made it sound so easy but didn't go into detail on how to do it exactly. I guess i'm worrying more than i should Normally i would just go outside and snap away till I got it right and if i didn't then ask. But since I'm cameraless right now It's drivng me nuts trying 2 figure out exactly how to do it without being able to just go and try it.
     
  10. ThomThomsk

    ThomThomsk TPF Noob!

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    I used this website to print a depth of field chart, which I laminated and carry in my camera bag. I find it an easy way to determine the distance to pre-focus, depending on the circumstances:

    http://www.dofmaster.com/doftable.html

    You enter your camera model or film size and the focal length, then it calculates the limits of the DOF at distances from 1 foot to infinity, for apertures from f1.4 to f32, and presents them in a handy chart. For example, on a Nikon dSLR with a 28mm lens the chart shows me that at f11 if I set the focus at 12 feet then my DOF will extend from 5' 10.3" to infinity.

    Of course if you use zooms or more than one prime lenses then you need to print different versions of the chart for different focal lengths, but that isn't a great hardship. Anyway, I find it useful, and you may too.

    Thom
     
  11. Happy Hour

    Happy Hour TPF Noob!

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    exactly what I wanted!!! Thank you!
     

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