Graflex.org

[Dober]

I just bought a nice 2x3 Crown Graphic, and have also picked up a two-cell Graflite flash and some #5 and #25 flashbulbs, and have a question about reasonble depth of field with the 105mm Ektar lens. I have to admit I have never been very good at math, and the formulas for determining DOF look a little tough to figure out to me.

Can anyone tell me roughly what should appear reasonably sharp at f11.0 if I focus at about 12 Feet? Based on the guide numbers for the flashbulbs and a 5" reflecter, it looks like I should be shooting at around f11, and I don't have much of a feel for how much DOF that will provide with the 105mm lens, having shot mostly with 35mm cameras with wide angle lenses in the past. I appreciate any help you can give me with this!

[danimal]

Hey Dober,

depth of field is a very inexact science, because what's "sharp enough" to me might not sharp enough to you. With that said, many things are pretty much constant at any given focal length. Infinity focus is one thing that's going to be more or less the same for 100mm/105mm lenses, and DOF is another. So, if you can scrounge up a depth of field chart for a 105mm lens on Nikon's or Schneider's websites, for example, you can apply that to your 105mm lens. You could even get a rough idea what your DOF will be by looking at the marks on a 100mm-ish lens for a 35mm camera.

Dan

[danimal]

Dober,

here's a depth of field table for a 105mm Mamiya lens. It should be close enough to use as a starting point for your 105mm.

Dan

[troublemaker]

Not to take anything away from those who can work with the math and understand how to use it, but I am one of those learn by doing sorts, and I would set the camera up on my tripod and let the lens tell me what it will do on the GG. Then run a test roll and let the film inform me as to the quality of sharpness (I am also comparing contraast between lenses when I do this) in a given range. I just did this with a Xenar 105 over the last couple evenings, and also with my Ektar 105 a few months ago. Though not at 12ft, I can share that at 6ft none of my vintage normal lenses for 2x3 will sufficiently focus the depth of a Speed Graphic 23,using it as the subject composition, being about 8" deep, and shot at f11. F16 is reasonably sharp, but f22 is nifty, and probably covers a little over a foot while f11 only covers about 5in. I found four different lenses to be pretty close where DOF is concerned. How's that for avoiding math. To me it is about the same amount of work to just set up the camera, less actually...and find that darned tape measure that keeps escaping...
regards,
Stephen Adams

[ This Message was edited by: troublemaker on 2004-10-28 23:17 ]

[glennfromwy]

I have a 105/3.7 Ektar on one of my baby Speeds and the depth of field at f/16 seems disappointingly shallow to me. At f/22 it gets very much better. I say this regarding landscape shots. I have not used flash with it, nor used it for anything closer than about 25 feet.

_________________
Glenn

"Wyoming - Where everybody is somebody else's weirdo"

[clnfrd]

Sounds to me like you need to use faster film...or "soup up" the film you're using when developing, so that you can stop down to f22...IF you need more DOF. But,closer objects are going to be over-exposed with your flash anyway, so, actually, why not just shoot the subject at 12' at f11? Fred

[Dober]

Thanks for all the great input guys! I did pop an R10 back on the camera last night and shot a test roll just to see what looked reasonably sharp at various distances. I double checked my guide number math, and it looks like I should use f16 at 12 ft., f11 at 16 ft., and f22 at 8 ft., so I might have at least a little ""wiggle room" with DOF, based on the mamiya DOF chart. I will get the film back today at lunch, so we will see how accurate the guide numbers are for my flash setup, as well as what looks reasonably sharp in the image (and I don't plan to enlarge very much so hopefully that will help as well). My kalart rangefinder is just a bit squinty and hard to really nail focus in lower light, which is why I asked about the DOF.

I am hoping to use this camera, as well as a 4x5 Crown Graphic I have, to do some event and street type photography not unlike how the cameras were (presumably) used by press photographers in the 40s and 50s. Gives you a whole new respect for those photographers, like Weegee, who took such great shots with these cameras, given their focussing limitations and slow shot to shot speed. If anyone has any thoughts or info on how the oldtime press photographers used these cameras, I would appreciate hearing about this as well.

Anyway, thanks a lot for your help, and I will post some of the photos I take --assuming I can remember to take out the darn dark slide!

[troublemaker]

You may be surprized how fast you will be able to shoot, and depending on how much you trust the RH-10 light seals, you may just leave the dark slide out at times when you need to move fast (carefull not to break it)but it becomes a very natural motion to pull it out in a very short time, like composing imgaes upside down on GG. Also, if speed is of the utmost and you can later crop, one can shoot from the RF as a centering point as opposed to moving the eye from RF to view finder of choice. My RFs all seem to center the image rather well when refernced to the GG or finders (provided that is the desired focussing point).
One thing I have noticed shooting the Graphics in public is they get me more attention than I desire, but also a certain amount of respect at places like car shows etc... At the Grand Canyon recently the tourists were posing for their own photos by my set up along the rim and repeatedly wanted to look at the GG, but of course they try and turn thier heads upside down. I call them knuckleheads, but the pretty girls get to turn the focussing knob...
Enjoy the nostalgia, and wait till you see the results ! Hand held 4x5; over 13 times the area of a 35mm. Crop to your hearts content and still be sharp with 400 film.
Stephen

[45PSS]

check out one of these caculators: search-depth of field-all the terms=
http://graflex.org/helpboard/viewtopic.php?topic=937&forum=10

_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.