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04-19-2010, 04:18 PM   #1
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K20d focusing with super telephoto lenses

I have recently adapted a Leica 400 6.8 telyt for birding and have difficulty getting shrp focus with manual lenses, even pentax lenses. What seems in focus isn't when viewed in the LCD and falls short of acceptable by 4x or 5x magnification. Anyone got suggestions on how to deal with manual focusing.

My Pentax 35 2.8 limited is sharp as a tack when Auto focused>superb lense by the way!

04-19-2010, 04:26 PM   #2
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If I were you I would take a look at the Katzeye focusing screen. This focusing screen looks like the one that came on older film cameras. This way it is much easier to focus using manual focusing lenses. I have not used one yet, but I have heard good things about them.

Here is a link:
KatzEye™ Optics - Custom Focusing Screens
04-19-2010, 04:29 PM   #3
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I'm not familiar with the Leica or the problems which may be inherent in that arrangement but I have an smc 1000mm and an A*400mm which I use with a K20D and I can tell you that it takes a while to get a feel for super-tele shooting. The sine qua non, of course, is rock solid support but--even with that in place--it just takes practice.
04-19-2010, 06:16 PM   #4
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I feel your pain. I added the Pentax ME53 eyecup for a 20% magnification boost that helped but still had too much trouble with manual focus and thin DOF. So last month I added a dual-diagonal split image screen from jinfinance for $31. With those two devices even my crappy eyes can get nice focus with all my manual lenses.

04-20-2010, 12:07 AM   #5
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QuoteOriginally posted by dadipentak Quote
I'm not familiar with the Leica or the problems which may be inherent in that arrangement but I have an smc 1000mm and an A*400mm which I use with a K20D and I can tell you that it takes a while to get a feel for super-tele shooting. The sine qua non, of course, is rock solid support but--even with that in place--it just takes practice.
Amen, amen, amen to that.
04-20-2010, 12:25 AM   #6
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QuoteOriginally posted by John Wiggs Quote
I have recently adapted a Leica 400 6.8 telyt for birding and have difficulty getting shrp focus with manual lenses, even pentax lenses. What seems in focus isn't when viewed in the LCD and falls short of acceptable by 4x or 5x magnification. Anyone got suggestions on how to deal with manual focusing.
John,

First of all you need rock steady support. When testing focus, you should also use either a remote release or the 2 sec. self-timer. Also make sure you turn the Shake Reduction OFF.

Then try to rig a shot with a tape measure that you can focus along, or maybe follow the procedure from Yvon Bourque: PENTAX DSLRs: PART-1. Autofocus Adjustment for the Pentax K20D, Custom Setting No 35

...to make sure your camera and lens is properly calibrated to each other. When testing this way, you got to trust the focus confirmation hexagon rather than your eyes.

I don't know your particular lens, but the Leica name do something to one's expectations, doesn't it? Even with the FA*600/4, I find that "sharpness" as evaluated on the camera LCD screen is abysmal. However there's more to sharpness than preceived detail. If the rendering from your lens has good contrast, the end product will look good even if fine detail looks a bit soft on the LCD.

hth,
Jostein
04-20-2010, 12:44 AM   #7
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K20 & manual focus

Hi John,
noticed with mine that diopter adjustment is critical with longer lens that I
shoot, Im 3 clicks from right on adjustment, Ive bumped it off in past by
accident and couldnt figure out what was happening right away.
Added Katz eye and magnifying eyepiece, that made huge difference.
04-20-2010, 09:09 AM   #8
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QuoteOriginally posted by John Wiggs Quote
I have recently adapted a Leica 400 6.8 telyt for birding and have difficulty getting shrp focus with manual lenses, even pentax lenses. What seems in focus isn't when viewed in the LCD and falls short of acceptable by 4x or 5x magnification. Anyone got suggestions on how to deal with manual focusing.
My Pentax 35 2.8 limited is sharp as a tack when Auto focused>superb lense by the way!
Figure out which is correct.. Your focus confirmation, or your eye. Do so by looking on a real display screen. The LCD on the camera is a nice info, and frame aid but really sucks as a photo viewer. They (the confirmation and your eye) may Both be perfectly fine but if they do not agree, you may need to re-shim your focusing screen. The need to do so is not uncommon. A Katzeye (or similar) will help but isn't the end all be all. Even if the split image looks perfectly aligned, even the slightest error will result in a less than sharp image. Also note that a different focusing screen may still require adjusting the shims to get the screen and the confirmation in sync.
When you get it sorted out, let's see some photos from that Leica. I'll bet they are stunning.


04-20-2010, 12:15 PM   #9
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Jostein: Thanks for your advice. The link is very informative.

QuoteOriginally posted by alunfoto Quote
John,

First of all you need rock steady support. When testing focus, you should also use either a remote release or the 2 sec. self-timer. Also make sure you turn the Shake Reduction OFF.

Then try to rig a shot with a tape measure that you can focus along, or maybe follow the procedure from Yvon Bourque: PENTAX DSLRs: PART-1. Autofocus Adjustment for the Pentax K20D, Custom Setting No 35

...to make sure your camera and lens is properly calibrated to each other. When testing this way, you got to trust the focus confirmation hexagon rather than your eyes.

I don't know your particular lens, but the Leica name do something to one's expectations, doesn't it? Even with the FA*600/4, I find that "sharpness" as evaluated on the camera LCD screen is abysmal. However there's more to sharpness than preceived detail. If the rendering from your lens has good contrast, the end product will look good even if fine detail looks a bit soft on the LCD.

hth,
Jostein
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