DOF and 4x5.

Discussion in 'Large Format Cameras and Accessories' started by kjsphoto, Jul 11, 2004.

  1. kjsphoto

    kjsphoto Subscriber

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    I have yet another question.

    With 4x5 what f-stop should no not go below. For example I was shooting a ridge in the distance today and the foreground was sharp but the treetops are a bit on the soft side. I was around f22 1/2 - 32 as I wanted to keep the speed up due to slight breezes in the canyons. It isn’t movement but soft.

    With MF I shoot between 22 and 32 and everything is fine.

    I also tilted the back to straighten the trees out and tilted the front a bit to pull the foreground in which it did.

    Any advice would be awesome.

    I knew when I was focusing that I would have to bring the F-stop down and when I looked through the GG and moved the setting on the lens it looked like it would have been enough to be sharp. Guess I was wrong.

    Man today was one of those days. Major bummer.

    Thanks,

    Kev
     
  2. jovo

    jovo Membership Council Council

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    It sounds like a problem caused by incorrect use of the tilts than one of depth of field. Without seeing what you were actually photographing it's hard to offer much advice that's very accurate, but: try leveling the camera completely; that'll straighten the trees. then, use front rise to get them all in if they're not already. Beyond that, use of movements unless you're trying to enlarge or reduce the foreground may be entirely unnessessary. There's an extensive article on focusing (including some use of movements) on www.largeformatphotography.info site. I've found it very helpful for my work with my 4x5.
     
  3. noseoil

    noseoil Member

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    Kevin, you can use any f-stop on the lens and not worry about a degraded image in most cases. The problem with f64 etc. often comes from the lens manufacturer's data sheets which can "see" a degradation of the image in the lab setting, but in terms of your eyes, there generally isn't a problem with most lenses. F22 is usually a good choice for most lenses, but movements may make this setting too shallow when depth of field considerations come into play.

    About focusing, you need to be very careful that movements are done with moderation. The near-far focusing technique takes a bit of time to learn, but having objects with great heighth in the mid ground can be problematic. This is one reason I like the 125mm lens length when possible. It's a good compromise between angle of view and depth of field. Many times, no movements are needed from 12' to infinity.

    That having been said, early morning is the time I prefer for shooting. Here in the desert, as soon as the sun comes up the winds start with the warming of the ground. Canyons need light, so this may not be possible in your area. A faster film will help, but give yourself time to learn. Large format has limitations, but the trade off in image quality is worth the effort. Take an even strain, my friend, and don't try to do it all at once. Small steps with pauses between for gratitude will help solve any problems which arise. The basics are important to learn, just allow enough time for the learning.
     
  4. kjsphoto

    kjsphoto Subscriber

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    Thank you all for the advice. My secarnio was like that in the article in link. I had a 3-D where I was trying to get everyting in sharp focus and I probably should have used any adjustments and just stopped down and used a faster film to keep the speed up. Live and learn.

    Well I think I am going to head back out today or tommorrow to give it another go. This was a different type of scene but I am still loving LF.

    Thanks again,

    Kev