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09-27-2007, 09:51 AM   #1
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Camera asks for focal length each time?

I have a "new" Pentax SMC A 50mm f/1.7 lens and when I power up my K100d, it asks me to confirm the focal length each time. Is this normal or is there a setting that lets me set it and forget it?

Also, focus wide open has to be very exact as I expected with the shallow DOF. I can't quite get the hang of the camera confirming focus with the red square. Should I be setting this to constant or single. It seems to flash briefly when I depress shutter release half way and then stop. Not enough time to work with MF.

Only had the lens one day and still figuring it out. Love the sharp pics so far.
Any input or observations welcome.

09-27-2007, 10:20 AM   #2
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The reason your camera is asking for the Focal Length is because the camera knows it's a manual focus lens and, it wants to know so it can correct the Shake Reduction properly. If you turn off SR it will stop asking. Also, when you enter 50mm for focal length, not only does it allow the SR to function properly, it will also embed the correct EXIF data..

With regards to your focusing issues..

Use MF.. The lens is MF. Forget about the little red square and look at the green hexagon in the viewfinder on the bottom. THAT is the focus indicator. It will turn solid when you are focused.

Use AF-S for using the 'trap focus' technique. With the camera set to AF-S depress the shutter fully and rotate the focus ring slowly until the shutter releases. The camera won't take a photo until it's in focus this way.
09-27-2007, 10:40 AM   #3
DMH
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Thanks Tom, I was looking in the wrong place in the VF. It all seems so simple when you do it correctly .

David
09-27-2007, 11:26 AM   #4
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Turn the red light off

QuoteOriginally posted by DMH Quote
I have a "new" Pentax SMC A 50mm f/1.7 lens and when I power up my K100d, it asks me to confirm the focal length each time. Is this normal or is there a setting that lets me set it and forget it?

Also, focus wide open has to be very exact as I expected with the shallow DOF. I can't quite get the hang of the camera confirming focus with the red square. Should I be setting this to constant or single. It seems to flash briefly when I depress shutter release half way and then stop. Not enough time to work with MF.

Only had the lens one day and still figuring it out. Love the sharp pics so far.
Any input or observations welcome.
I don't remember the menu setting but you can turn the red light focus off and just use the green light . I find it much easier to use.

Ken

09-27-2007, 11:51 AM   #5
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No problem man..
09-27-2007, 11:55 AM   #6
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QuoteOriginally posted by regken Quote
I don't remember the menu setting but you can turn the red light focus off and just use the green light . I find it much easier to use.

Ken
I keep forgetting to look at the green hex myself, concentrating instead on the red square. Sadly, I admit this has caused some blurry shots worthy of a 5 yr old photog

I'll be taking out the little red square option as soon as I get home tonight.

Love this forum - thanks regken!
09-27-2007, 01:17 PM   #7
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Thanks for those tips guys. Thanks for the question too.
09-27-2007, 02:40 PM   #8
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An added point re manual focus lens....

The neat thing about the SR focal length setting is that the camera remembers and shows the selected settings each time you turn on the camera until you change lenses again. Just a touch of the shutter release ends the message display.

09-27-2007, 04:47 PM   #9
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QuoteOriginally posted by dmdctusa Quote
An added point re manual focus lens....

The neat thing about the SR focal length setting is that the camera remembers and shows the selected settings each time you turn on the camera until you change lenses again. Just a touch of the shutter release ends the message display.
Hah! Now that's something i didn't know!! I swear I have been hitting the OK button. I did know that you could just turn on the camera and shoot but, I really though the camera would not adjust properly without telling it what it was. Knowing it 'remembers' is a great thing!!
09-28-2007, 03:33 AM   #10
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Just to confirm my thought - its appropriate to set the actual focal length of the lens in question and not necessarily the cropped mm rating, correct?

(for example, if I toss a 50mm on, I input 50, as opposed to 75?)


Thx
09-28-2007, 04:09 AM   #11
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Correct

QuoteOriginally posted by thePiRaTE!! Quote
Just to confirm my thought - its appropriate to set the actual focal length of the lens in question and not necessarily the cropped mm rating, correct?

(for example, if I toss a 50mm on, I input 50, as opposed to 75?)


Thx
ALWAYS think in terms of real mm. It will save you time and endless debates about FOV and focal length.

Regards,

Ken
09-28-2007, 05:43 AM   #12
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QuoteOriginally posted by thePiRaTE!! Quote
Just to confirm my thought - its appropriate to set the actual focal length of the lens in question and not necessarily the cropped mm rating, correct?

(for example, if I toss a 50mm on, I input 50, as opposed to 75?)


Thx
Yes, you enter 50mm. I too had the same question when I first got the K10D as it was the first camera I've ever owned that even had such a feature.
09-28-2007, 06:29 AM   #13
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I agree with turning off the red square auto-focus point indicator. It's really as pointless as tits on a boar hog if one is using manual focus lenses. The green hex is good, but nothing beats swapping out the matte screen for a split-prism if using manual focus lenses is going to be more than an occasional thing.

As for the focal length: If you're still at the same focal length, you don't have to bother with hitting the OK button on the back. Just tap the shutter button lightly and you're good to go.
09-28-2007, 07:01 AM   #14
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Doesn't the split screen affect exposure on K100d?

I've read a few posts about changing the focus screen on the K100d which seems to be quite simple but some have reported that they have to compensate with the exposure. Anyone had first hand experience, and, is there a supplier you can recommend in Canada or the US?
09-28-2007, 07:33 AM   #15
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I use a Chinese screen that requires about a 0.5+ bump. No big deal and most certainly a worthwhile trade-off in my opinion. I have to dash off to work and don't have time to hunt up the link for the guy I purchased my screen from, but a search on the forum using "screen" and "China" as search terms should yield some useful info and links.
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