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Old Aug 10, 2006, 10:30 PM   #11
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Dana-

However, I think that we would indeed be QUITE remiss, if we did not recognize the fact that the Pentax 18-55mm lens, as a THE kit lens works very well indeed on virtually all models of the Pentax DSLR stable, all the way through the K100D.

MT/Sarah
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Old Aug 11, 2006, 8:38 AM   #12
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I am getting mixed up AGAIN - please someone explain to me once and for all. I was told that all lengths are quoted in 35mm terms - therefore x-300mm is really a (times 1.6) x-480mm on a digital. Is the 18-35mm film lens a 28-55mm approx on a digital.

I've seen everyone quote this FAJ, DA, AF, Fa, M, A etc which most of the time I've ignored because I've never really been a "techie" photographer should I be paying more attention to this? The 18-35 doesn't have FAJ written on it so how the in h does one recognise these things.

Dana, glad you came out and used this thread for your first post - Welcome.
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Old Aug 11, 2006, 8:59 AM   #13
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Sarah,
Agreed, the 18-55mm is a very good kit lens. Highly rated by users. I still shoot film about 30% of the time so I'm more familiar with the full frame glass. Haven't yet purchased a DA series lens, the 14mm,f2.8 is looking very interesting to me :-)

Dana
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Old Aug 11, 2006, 9:30 AM   #14
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All lens are quoted in 35mm lengths. If you take this length and multiply it by the 1.5 crop factor you will get the Field of Veiw that the lense provides on a Pentax Dslr.The 18-35mm lens will give you a Field of Veiw similar to a 27-52mm lens. Field of Veiw describes how the image is captured on the aps size sensor. It doesn't magnify anything. A 300mm telephoto is still 300mm, not 450mm. The FOV on the other hand
will appear as 450mm. It's like cropping the center out of your shot.

Faj, Fa, F.........these are just Pentax lense designations describing features of the lense. The link I posted earlier has a wealth of info about the Pentax line. I'm a bit 'Techie' and know what the abreviations mean, but when shopping for a lense I figure out what I'm looking for and check all ratings. If I can; I'll shoot one first. With Pentax's ability to use all the old glass, there's a big selection out there.

Thanks for the welcome.

Dana
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Old Aug 11, 2006, 11:09 AM   #15
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nlp239 wrote:
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I am getting mixed up AGAIN - please someone explain to me once and for all. I was told that all lengths are quoted in 35mm terms - therefore x-300mm is really a (times 1.6) x-480mm on a digital. Is the 18-35mm film lens a 28-55mm approx on a digital.
They are really what it says on them, 18-55 mm, 50-200 mm, 300 mm etc. BUT since the CCD sensor is smaller than a traditional film negative, when the picture is enlarged to a copy they give you the effect of a lens that is 1,5 times longer than if the same lens is used on a traditional film camera. Sothey give you pictures as if they would have been 27-82.5, 75-300, 450 etcon a film camera.

Mostphotographers use this "old" measure because they are familiar with it. Compare with horse powers, it made sense when most people could refer to the strenght of a horse and wanted to know how strong the car engine was.

Kjell

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Old Aug 11, 2006, 2:01 PM   #16
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The FA, F, A etc. is important if you want to know how the lens will talk to the camera.

I don't know all the fine points, but basically, if you want auto-focus, look for a lens with either F, FA or DA. The F and FA will work on a film camera, DA lenses are digital only. The FAJ lenses are similar to the DA lenses (don't have an aperture ring, so can only be operated by the camera) but can be used on film cameras.

"A" lenses without an F or aDhave the ability to have the aperture controlled by the camera, but won't auto focus.

M or K lenses are strictly manual lenses - they won't talk to the camera electronically. There is a lever on them where the camera can stop down the lens when you take the picture, so you can focus with the lens wide open (try focusing a lens stopped down to F22 - it's dark!).

The screw mount lenses don't have that capability, so you'd have to stop down the lens yourself (there's been conversations here about doing that - I've never used one of these lenses).

So those letters tell you whether the camera will be able to set the exposure for you and/or the focus, all nice things to know if you are buying used lenses.
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Old Aug 13, 2006, 9:02 AM   #17
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Everyone Thanks. I got the abreviations and although I understand horsepower I don't understand this FOV thing. I have a regular 50mm lens on a 35mm film camera right? I put that same lens on dslr with a crop factor of 1.6 - what do I see thru the viewfinder?????

You say I'm seeing a croped image but it's not magnified or enlarged????

I'm a little thick so if you want to give up go ahead.
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Old Aug 13, 2006, 9:41 AM   #18
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nlp239 wrote:
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Everyone Thanks. I got the abreviations and although I understand horsepower I don't understand this FOV thing. I have a regular 50mm lens on a 35mm film camera right? I put that same lens on dslr with a crop factor of 1.6 - what do I see thru the viewfinder?????

An image similar to a 75mm lens

You say I'm seeing a croped image but it's not magnified or enlarged????

It's not magnified, when you print the images, 35mm vs. digi , if will appear enlarged.
Simply because your capturing a smaller FOV with the digi. When you use a tele lens you magnify the subject, it also compresses the image, all objects appear closer together than they really are. The FOV factor doesn't do this compression.

I'm a little thick so if you want to give up go ahead.

Simple way to understand , mount the lens on the film body, either look thru it or take a shot. Do the same with the digi. You'll see the difference in FOV.
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Old Aug 13, 2006, 11:43 AM   #19
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nlp239 wrote:
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I have a regular 50mm lens on a 35mm film camera right? I put that same lens on dslr with a crop factor of 1.6 - what do I see thru the viewfinder?????
You see your soon-to-be picture. If you put an old film camera just beside your DSLR you will have to put a 75 mm lens on the film camera to see the same view. In the other direction, if you put the 50 mm lens on the film body you'll have to put a 35 mm lens on your DSR to see the same view.

If I put my Super program with the 600 mm lens on it, and the DS with my 200 mm+2Xteleconverter making the lens a 400 mm just beside, point both at the same flowerI see just as much of the flower thru both viewfinders. (I've done that to check if this crop factor is really true. It is.)

Advantage: your tele lenses give you more tele on the DSLR than on a film body. Shorter teles are cheaper than longer teles.

Disadvantage: when you want wide angel, you must use an even shorter lens on the DSLR than on a film body to get as wide an angel in your picture. Shorter wide angels are more expensive than not so short ones.

Keep on asking. We wont give up till you say "yeah, it's all clear to me now!"

Kjell
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Old Aug 13, 2006, 12:56 PM   #20
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Quote:
Keep on asking. We wont give up till you say "yeah, it's all clear to me now!"
Thanks Kjell and Dazooo. I think, hope I'm not wrong, we're saying the same thing in different ways - or at least I'm comprehending things the way my unique mind works (Something like the Little Prince and the Fox).

Anyhow, would the image below describe what we're saying?


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