Believe it of not, older Dagors do exist...
http://www.largeformatphotography.in...or-Focus-Shift
"I love my Verito lens, but I always have to sharpen everything in Photoshop..."
Yes, they make great paperweights and I don't use them, or the ones with focus shift! Quality control was not great back then, the bad ones often end up at auction on the site.
Sadly, not a joke. I consider myself a slightly better than average photographer and know just enough about electronics to follow along when an EE's going over a schematic. Once I left the still/motion picture production world, I worked for a time as a video editor, then transitioned to product support and marketing for an edit console manufacturer and, later, Sony Broadcast. I asked more than one engineer over the years to teach me the basics of 'scope use but since I was a film school grad and "the marketing guy", the training was "just fiddle with the knobs until you get what you want on screen." Now that I'm retired, learning large format photography is more appealing to me than making another run at 'scopes.
"The Ground Glass is truth".
If you don't see it there you don't have it.
Drew Bedo
www.quietlightphoto.com
http://www.artsyhome.com/author/drew-bedo
There are only three types of mounting flanges; too big, too small and wrong thread!
Yeah, I get where you're coming from. I think what you need is a function generator to go with your scope (you can actually download them as an app for your phone). Once you get that, then you can see how the scope works. The trick to using a scope is knowing what signal to expect. Then, you can measure the signal you get and see how it compares to what you'd expect (or see how the output varies from the input), and now you know a little bit about what's going on in the circuit. If you're not familiar with scopes and just looking at a screen full of white noise or a flat line, you're not gonna have a good time.
I agree that the Sinar calculator is the easiest method out there. My first LF camera was a Sinar F1, and I didn't realize how useful that thing was until I got my second LF camera that didn't have one! With my other cameras, I usually try to mimic the Sinar calculator. Basically, I focus on whatever is closest that I want in sharp focus and then note where the standard lies (front or rear, depending on which one I'm moving to focus). Then I focus on what is farthest that I want in sharp focus, and then note the where the standard lies this time. Then I move the standards half way in between the two, and stop down as far as I feel comfortable, and cross my fingers and hope for the best! It usually works.
Jim, there are several brands of LF cameras that have assymetrical axis movements and built in calculators, some, like Linhof, have continuously variable points as opposed to the single point on a Sinar!
In addition, the very simple, pocket Rodenstock depth of field/Scheimpflug calculator calculates both for any format camera from 810 to 35mm. Eliminates crossing your fingers and always works!
I downloaded the book and found it quite interesting. However I’m at a loss to see how factor J is determined.
In Figure 5 it is stated that J is the height of the lens above the plane of sharp focus and later attributes a value of 8.5 feet to J. BUT nowhere [that I have found] is there a description as to how J is computed. It is obviously a geometric construction, but the out of scale diagram (albeit very clear) does not enable the geometric/mathematical construction to be determined.
Many of the tables list relationships involving J, but no explanation as to how it is determined.
In chapter 10 – Summary - it is stated “estimate the distance from the lens to the plane of sharp focus measured in a direction parallel to the film place - this is the distance J. Again no explanation as to how J is determined - so how can it be meaningfully be estimated.
I found no links to contact the author, hence this posting.
Regards
Tony
I have both of his books and they are quite interesting... but really, it just complicates things more than it has to be. I use Howard Bond's technique of picking a point on the top and bottom of the GG... then tilt (or swing) and focus until both points are focused.
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