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04-06-2009, 10:24 PM   #31
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QuoteOriginally posted by aweir Quote
Help me finally understand this...The FA35mm is for film SLRs so on a DSLR it would be the equivalent of a 50mm lens, right? Now is the DA35mm already "made for dslr"? If so, does that mean that the focal length of a DA35mm is equivalent to 35mm on digital or is it still equivalent to 50mm? In other words if I took the DA35mm would it give me a wider FOV than the FA35mm on a DSLR?

I always assumed that a tell-tale sign of a "made for dslr" lens was that it had NO aperture ring. So that a 50mm lens IS a 50mm and not 75mm....

I find this most confusing.
"Made for dslr" means it's optimized for the cropped sensor, nothing more. That means it doesn't use unnecessary glass (since it covers a smaller sensor), can be made smaller/compact etc and yes they remove the aperture ring since DLSRs electronically control the aperture. It still is equivalent to the 50mm FOV in a film/FF SLR.

So try both the DA35 and FA35 and they'll give you the exact FOV

04-06-2009, 10:49 PM   #32
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thank you for the quick reply. My understanding is clearer now.

So in order to get a true "35mm film-equivilent focal length":

(x)(1.5)=35
X=24

you would need a 24mm lens to equal the 35mm lens on a film camera. Now I understand.

I'm beginning to see the limitations of the 1.5 crop factor. I wonder how many people mistakenly buy a 50mm lens for their dslr, thinking it's a "normal" lens. It's normal in one sense (the actual focal length of the lens itself), but not another (the focal length equivalent to a 35mm camera) after the crop factor.

Thus any "made for dslr" 50mm should NOT be labeled as "normal" because it's not.
04-06-2009, 10:56 PM   #33
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Well darn it I just bought the DA100mm f/2.8 macro thinking that it would be the equivalent of 100mm on film. I honestly thought that the crop factor was already compensated for when the lens is advertised. :ugh: I thought that the DA lenses were considered "35mm equivalent lenses".
04-07-2009, 12:36 AM   #34
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Yup now you got it! The DA21 would also make a nice 35mm-ish focal length

Edit: I'm talking about FOV here okay??


Last edited by soccerjoe5; 04-07-2009 at 02:00 AM.
04-07-2009, 12:44 AM   #35
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It's sad that it took an epiphany to realize that...

Now I'm beginning to think I have WAAAY too many lenses

10-17mm fisheye Pentax
18-250mm Pentax
28-80mm 1:2 macro Sigma
80-200 Promaster
100mm f/2.8 1:1 macro Pentax
70-300mm Tamron
17-50mm f/2.8 Tamron
18-55mm Pentax kit lens
55-300mm Pentax
FA35mm f/2.0 Pentax

and soon,
FA50mm f/1.4 Pentax
Sigma 10-20mm OR Pentax 12-24mm

Last edited by aweir; 04-07-2009 at 12:51 AM.
04-07-2009, 01:21 AM   #36
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I don't think you can have too many lenses, as long as you take photos with them
04-07-2009, 01:30 AM   #37
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Sorry, but you´re wrong. The focal length does not change. 21mm are 21mm. Smaller Sensor > smaller angle at the picture, nothing else!
04-07-2009, 01:59 AM   #38
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QuoteOriginally posted by quickiekuchen Quote
Sorry, but you´re wrong. The focal length does not change. 21mm are 21mm. Smaller Sensor > smaller angle at the picture, nothing else!
Who said anything otherwise? I was talking about FOV. of course 21mm is 21mm

04-07-2009, 02:08 AM   #39
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Sorry, missunderstood!
04-07-2009, 02:11 AM   #40
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QuoteOriginally posted by quickiekuchen Quote
Sorry, missunderstood!
No problemo!
04-07-2009, 06:02 AM   #41
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QuoteOriginally posted by aweir Quote
Help me finally understand this...The FA35mm is for film SLRs so on a DSLR it would be the equivalent of a 50mm lens, right? Now is the DA35mm already "made for dslr"? If so, does that mean that the focal length of a DA35mm is equivalent to 35mm on digital or is it still equivalent to 50mm? In other words if I took the DA35mm would it give me a wider FOV than the FA35mm on a DSLR?

I always assumed that a tell-tale sign of a "made for dslr" lens was that it had NO aperture ring. So that a 50mm lens IS a 50mm and not 75mm....

I find this most confusing.
It is confusing. The DA lenses are marked with full frame measurements. The DA 35mm Macro has the same 52.5mm equiv. field of view as the full frame FA 35mm f/2.
04-07-2009, 09:19 AM   #42
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QuoteOriginally posted by quickiekuchen Quote
Sorry, but you´re wrong. The focal length does not change. 21mm are 21mm. Smaller Sensor > smaller angle at the picture, nothing else!
There's no need to cause anymore confusion. The issue has been resolved. A 35mm "made for film" has the same FOV on a dslr as a state-of-the-art "made for digital" DA 35mm on a dslr. Yes, FOV changes from film to digital with the same focal length lens.
04-07-2009, 09:21 AM   #43
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QuoteOriginally posted by aweir Quote
There's no need to cause anymore confusion. The issue has been resolved. A 35mm "made for film" has the same FOV on a dslr as a state-of-the-art "made for digital" DA 35mm on a dslr.
There should really be a sticky about crop factor, focal length and FOV!
04-07-2009, 12:58 PM   #44
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QuoteOriginally posted by farfisa Quote
There should really be a sticky about crop factor, focal length and FOV!
Yeah I think so too. This whole debate keeps popping up haha!
04-07-2009, 01:32 PM   #45
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QuoteOriginally posted by soccerjoe5 Quote
Yeah I think so too. This whole debate keeps popping up haha!
I think you meant to say it keeps "cropping up"
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