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12-14-2012, 04:13 PM   #1
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Anyone tried drawing distance scales on DA 35mm?

Has anyone tried drawing distance scales on a DA 35mm f2.4? I know the focus throw is very short, but at least min distance, infinity, and a couple values in between.. How would one go about doing that? Is there any reason why it wouldn't work?


12-14-2012, 06:09 PM   #2
dms
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I don't know about that lens, but I have added a depth of field scale for the widest FL, on an old nikon 35-70 mm zoom lens, and also a more detailed magnification (m) scale on a VS1 90mm f2.5. Both were MF lenses--but if it has a smooth barrel with enough clearance for thin paper and scotch tape you can work out a scale. Pretty standard practice on older MF lenses anyway. I recalled Ansel Adams speaks to adding focusing scales (in Camera and Lens), although what he has seems to be a bit odd--on quick glance now.
12-15-2012, 12:52 PM   #3
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It seems like the scale from an FA 35/2 should work but on the FA, it's behind a window.
12-22-2012, 07:10 AM   #4
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QuoteOriginally posted by dms Quote
I don't know about that lens, but I have added a depth of field scale for the widest FL
Interesting. How did you add that? Just added objects in front, measured how far they are, and then marked the spot on the focus ring?

QuoteOriginally posted by Just1MoreDave Quote
It seems like the scale from an FA 35/2 should work but on the FA, it's behind a window.
Possibly, but I thought the FA has a longer focus throw.

12-22-2012, 11:14 AM - 1 Like   #5
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Cut and held a piece of paper (it was decades ago--forgot if it was on semi-clear velum or graph paper) onto the lens barrel and marked the existing distance markings, then prepare a detailed set of intermediate distances on the same paper, and mark the depth of field (near and far) from standard tables. The details depend on the lens construction--I have never done it for AF lens--and only did depth of field on a Nikon (35-70mm zoom) .

As I recall I did it for 35mm and f/16. On a 2 ring zoom you likely can only do it for one FL (presumably do for the widest FL). Even simpler is to identify the hyperfocal distance vs FL and fstop--which is the most useful for street shooting.

If using 35mm (FF) tables for depth of field don't forget to use the depth of field for 1 stop more open (because of smaller sensor, and thus more magnification for same size print). e.g., for lens set at f/16 the depth of field listed for f/11 should be used.
12-22-2012, 11:25 AM   #6
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I forgot to mention--to add intermediate distances I believe I graphed the existing distance values versus their relative position, drew a smooth curve through the points, and then picked off the intermediate positions. Or I may have used Adam's equation mentioned above (Ansel Adams, "Camera and Lens," 1970, page 110). For this part if problematic you may have know a scientist/engineer who can help with the equation/plot.
12-22-2012, 11:33 AM   #7
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There are DOF and Hyperfocal Distance charts online you can print out and carry in your bag. I use the DOF Calculator Android app, another useful thing a smart phone has. You enter your camera (Pentax is listed), focal length, and f stop and it will give you the amount of DOF you have at any distance.
12-22-2012, 12:40 PM   #8
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If the point is to have a rapid depth of field--as in street shooting where you see a fleeting scene, AND QUICKLY (split second) zone focus the camera and shoot--tables and calculators are not useful. For other situations yes.

Although not ideal I also have the following hyperfocal distances on my lens hoods.

1.5 crop sensor
hyperfocal (ft) at
FL f/22 f/16 f/11 f/8
21 3 4 6 8
28 5 7 10 14
35 8 12 16 24

01-13-2013, 08:29 PM - 1 Like   #9
dms
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(If my attaching a photo works)--this is a photo of my added on DOF. There are a few things wrong/I would have changed, but I traded the lens for another. It was just given back to me so I took a photo for you.
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