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08-01-2008, 03:22 PM   #1
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Understand 50mm with K200D

I have 50mm lens that I attached to my Pentax K200D. It asks me to enter the focal length of the lens. Should I enter 50mm or should I enter the value based on the sensor crop (1.5 X) of 35mm. Or did I get it all wrong.

Some help would be appreciated.

Thanks

08-01-2008, 03:29 PM   #2
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Put in 50mm, as the SR calculates the length without the crop.

a 50mm will still be a 50mm lens, even if the effective FOV is 75mm.
08-05-2008, 01:52 PM   #3
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Thanks for the reply, I put in 50mm, really like the lens.
08-05-2008, 06:57 PM   #4
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A focal length is a focal length, it never changes (unless you have a zoom ). The 1.5x crop is for the field of view provided, to make it easyer for people used to 35mm film, not the actual focal lenth, so for anything besides calculating FOV based on the 35mm standard, use the actual focal length instead.

08-06-2008, 03:49 AM   #5
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Does the camera ask you to put in focal length? How? I have a K10D and he has never asked me anything (except for "do you still love me even though K20D is here?") .

Is that a new function or anything?
08-06-2008, 04:00 AM   #6
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It will ask you for the focal length if you have the following:

1. SR on
2. Have a manual lens on the camera

2 is important since older lenses cannot communicate the focal length to the camera so the user needs to input the length manually for SR to compensate correctly.
08-06-2008, 04:29 AM   #7
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QuoteOriginally posted by MrApollinax Quote
It will ask you for the focal length if you have the following:

1. SR on
2. Have a manual lens on the camera

2 is important since older lenses cannot communicate the focal length to the camera so the user needs to input the length manually for SR to compensate correctly.
Ahaa... thanks! I only have FA and DA lenses so that's why I don't get that question. Thanks!
08-06-2008, 07:31 AM   #8
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QuoteOriginally posted by josekj Quote
I have 50mm lens that I attached to my Pentax K200D. It asks me to enter the focal length of the lens. Should I enter 50mm or should I enter the value based on the sensor crop (1.5 X) of 35mm. Or did I get it all wrong.

Some help would be appreciated.

Thanks
There is no such thing as a crop factor. A group of internet buffoons decided to come up with this concept in order to allow them to be mush brained idiots.
Learn to think of your lenses in terms of what they will do on the format you are using, not on some format you are not using.

And enter the focal length of the lens in use into the camera's shake reduction screen. The camera is smarter than it's user base from the looks of it. It doesn't care about silly crop factors.

08-06-2008, 07:38 AM   #9
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QuoteOriginally posted by Wheatfield Quote
There is no such thing as a crop factor.
Of course there is. It's 2/3
08-06-2008, 07:42 AM   #10
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QuoteOriginally posted by Wheatfield Quote
There is no such thing as a crop factor. A group of internet buffoons decided to come up with this concept in order to allow them to be mush brained idiots.
Learn to think of your lenses in terms of what they will do on the format you are using, not on some format you are not using.
Crop factor is an extremely useful way of comparing FOV on differing lens systems. It allows me to compare for example the zoom factor of my Canon A720 (36-210mm) with my DSLR lenses (24-450mm). How would you describe how an Olympus E-510 looks with a 300mm lens without crop factor or 35mm equivalent? Because it sure looks a lot different than a 300mm lens on a Pentax, i.e. 600mm vs 450mm.
08-20-2008, 02:29 PM   #11
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Why does Pentax call it Kit lens 18-55mm lens (which in 35mm language - 28-82.5mm). Why do they use those terms to descibe lens. I understand that those lens can only be used with camera that have a 1.5X crop. Is that true?
08-20-2008, 02:40 PM   #12
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QuoteOriginally posted by josekj Quote
Why does Pentax call it Kit lens 18-55mm lens (which in 35mm language - 28-82.5mm). Why do they use those terms to descibe lens. I understand that those lens can only be used with camera that have a 1.5X crop. Is that true?
Because the lens has a focal length of 18-55 mm. "Focal length" is a defined "scientific" term and it means something in particular when applied to lenses. Regardless of what size sensor you put inside the camera, the lens doesn't change and it has a true focal length of 18-55 mm.

Focal length - Wikipedia, the free encyclopedia
08-20-2008, 03:04 PM   #13
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I shoot 2 1/4 x 1 3/4, and, as far as I can remember, there was never a "crop factor" when comparing it to 35 mm cameras. There is no such thing as "crop factor", just an equivalent field of view. The APS-C sensor is not cropped, so why come with a "crop factor".
08-20-2008, 06:38 PM   #14
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Because it's a lens which zooms from 18mm to 55mm?

QuoteOriginally posted by josekj Quote
Why does Pentax call it Kit lens 18-55mm lens
08-20-2008, 10:50 PM   #15
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No one ever compared the medium format to the 35mm format. The 35mm format is the standard by which most hand held cameras are compared. So there for The term 35mm equivent has been used for some time now. The term crop factor is just used to describe the field of view. They used to call it the focal lenght multiplyer until somebody complained. A term that is in common use does exist of course.

Dave

QuoteOriginally posted by flyer Quote
I shoot 2 1/4 x 1 3/4, and, as far as I can remember, there was never a "crop factor" when comparing it to 35 mm cameras. There is no such thing as "crop factor", just an equivalent field of view. The APS-C sensor is not cropped, so why come with a "crop factor".
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