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10-15-2009, 04:12 PM   #16
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QuoteOriginally posted by Russell-Evans Quote
This isn't correct as your using the marketing numbers on the 10-17mm and why I posted the ideal lens calculated values, i.e. best case numbers.
The numbers I'm using came from Pentax's website and are quoted for these specific lenses, so they may be more accurate than theoretical calculations. Or at least have an equivalent amount of marketing fib in them.

10-15-2009, 07:08 PM   #17
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QuoteOriginally posted by audiobomber Quote
The numbers I'm using came from Pentax's website and are quoted for these specific lenses, so they may be more accurate than theoretical calculations. Or at least have an equivalent amount of marketing fib in them.
No, the FOV being quoted for the fisheye on the Pentax site is the whole image circle FOV. The FOV being quoted the normal lenses is the HFOV. They are completely different measurements and to use them in a comparison is an error.

The ideal calculated values are the maximum. As you are quoting the fisheye as being over the calculated ideal, it is inaccurate from the start. There is no way to spin this, compare the same FOV measurements, simple.

Thank you
Russell

Last edited by Russell-Evans; 10-15-2009 at 07:15 PM.
10-15-2009, 08:36 PM   #18
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QuoteOriginally posted by Russell-Evans Quote
No, the FOV being quoted for the fisheye on the Pentax site is the whole image circle FOV. The FOV being quoted the normal lenses is the HFOV. They are completely different measurements and to use them in a comparison is an error.

The ideal calculated values are the maximum. As you are quoting the fisheye as being over the calculated ideal, it is inaccurate from the start. There is no way to spin this, compare the same FOV measurements, simple.

Thank you
Russell
Actually, if you look at the numbers you posted, they confirm the ones posted by others. AFAIK, all FOV numbers for lenses are given as the diagonal.

audiobomber stated:

16-45mm: 83-35

you stated:

For normal lens at 16mm
VFOV
72.82 deg
HFOV
51.69 deg
FOV min. image circle
82.84 deg

They may have rounded, but that's practically the same number.

QuoteOriginally posted by Russell-Evans Quote
This isn't correct as your using the marketing numbers on the 10-17mm and why I posted the ideal lens calculated values, i.e. best case numbers.
If we want to split hairs, technically, your numbers can also be called incorrect. At least, with respect to Pentax sensors sizes.

You apparently used the Nikon D1/DX as the basis. It has a sensor size of 23.6 x 15.5mm.

I believe the sensor size for Pentax cameras are:

K20d/k-7 =23.4 x 15.6 mm
all other Pentax=23.5 x 15.7mm

One thing the Pano Calculator reveals though, is some inaccuracy of specified angle of view for lenses on different sized sensors. Sigma states the angle of view of the 10-20mm is "102.4 - 63.8 degrees". But this is only true on a Sigma DSLR sensor (20.7x13.8mm). On the k20d/k-7 this range becomes 109.16 - 70.21 degrees.

This then accounts for my own error when I said the Sigma 10-20 is just over 100 degrees at 10mm.

QuoteOriginally posted by Russell-Evans Quote
This isn't correct as your using the marketing numbers on the 10-17mm and why I posted the ideal lens calculated values, i.e. best case numbers.
I'm no expert on this, but since the numbers lined up, I'm guessing "FOV min image circle" is the diameter of the circle produced by the lens as it falls upon the sensor. This number, as you saw above, corresponds with the angle of view typically given for lenses. This angle of view is a diagonal one.
10-15-2009, 09:29 PM   #19
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Thanks to all who provided info. I have been thinking about the info...it sounds like a decision between the Pentax 12-24 and the Pentax 10-17 Fisheye.

I like the possibilities with the 10-17. I really appreciated the angles of view, anecdotal experiences, two pix of the FE at 17 mm and 16-45 at 16mm, the analytical comments and the links to the pictures .

Please continue to add comments, picture comparisons, etc. Much appreciated.

les

10-16-2009, 01:09 PM   #20
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Just to get an idea of the angle of view and the distortion of the fish eye, here is a comparison of the rectilinear DA 15mm (87 degrees) and the DA 10-17mm FE at 17mm (98 degrees). These angles are for my k-m. [edit]I was roughly at the same distance for both pictures.



In the top corners of the FE side you can see the edges of the ceiling peeking in.

Last edited by wasser; 10-16-2009 at 01:52 PM.
10-16-2009, 01:28 PM   #21
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QuoteOriginally posted by wasser Quote
Just to get an idea of the angle of view and the distortion of the fish eye, here is a comparison of the rectilinear DA 15mm (87 degrees) and the DA 10-17mm FE at 17mm (98 degrees). These angles are for my k-m.
The OP should use his 16-45 for a photo like that.... Unless he wants to bring a little flair to a boring subject, then twist that 10-17 up to 10mm and let 'er rip.

PS I assume you were standing closer to the subject with the fisheye?
10-16-2009, 01:53 PM   #22
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QuoteOriginally posted by audiobomber Quote
PS I assume you were standing closer to the subject with the fisheye?
Actually, I was at roughly the same distance for each photo. It's a bit featureless and the white wall space doesn't really reveal it well, but the FE is capturing a wider area. It goes from the ceiling to just a bit above the floor. I probably should have done one with detail right to the edges, especially since that's where the distortion is the most pronounced.
10-16-2009, 07:39 PM   #23
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QuoteOriginally posted by lesmore49 Quote
Please continue to add comments, picture comparisons, etc. Much appreciated.

les
The fisheye effect is easily managed. It can be subtle, or not. Here's a shot at 10mm where the fisheye effect is downplayed. At 180 degrees fov, you have to mind that you don't get your feet into the shot.




Or you can get crazy with the distortion to add interest to an otherwise ho-hum scene. Honestly, I'd never trade my 10-17 for a super-wide rectilinear lens.





If the 10-17 was a Sigma or Tamron, it would definitely be labelled a Macro lens.





Last edited by audiobomber; 10-16-2009 at 08:19 PM.
10-16-2009, 08:21 PM   #24
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QuoteOriginally posted by audiobomber Quote
The fisheye effect is easily managed. It can be subtle, or not. Here's a shot at 10mm where the fisheye effect is downplayed. At 180 degrees fov, you have to mind that you don't get your feet into the shot.




Or you can get crazy with the distortion to add interest to an otherwise ho-hum scene. Honestly, I'd never trade my 10-17 for a super-wide rectilinear lens.





If the 10-17 was a Sigma or Tamron, it would definitely be labelled a Macro lens.


Audiobomber,

Thank you very much for those photos with the len's setting listed. That pix of the outdoor water scene taken at 10 mm is great. This is exactly what I wanted. As you say you can almost get a level pix at 19 mm with the 10-17...by careful positioning. I'm assuming you held the lens low and level ?

After seeing this photo at 10mm I'm about 90 % certain that the Pentax 10-17 FE is the one for me.

Thanks, les
10-16-2009, 10:02 PM   #25
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QuoteOriginally posted by lesmore49 Quote
Audiobomber,

Thank you very much for those photos with the len's setting listed. That pix of the outdoor water scene taken at 10 mm is great. This is exactly what I wanted. As you say you can almost get a level pix at 19 mm with the 10-17...by careful positioning. I'm assuming you held the lens low and level ?

After seeing this photo at 10mm I'm about 90 % certain that the Pentax 10-17 FE is the one for me.

Thanks, les
All three of the photos in that post were taken at 10mm. I had to level the slate waterfall in Picasa.

QuoteOriginally posted by lesmore49 Quote
After seeing this photo at 10mm I'm about 90 % certain that the Pentax 10-17 FE is the one for me.
I don't go around recommending a 10-17 fisheye to everyone who wants a super wide angle (although they should all at least consider it). You seem to enjoy the FE effect; not everyone does. Your 16-45 has a pretty capable wide end, and will do a lot of what a regular SW does.

I find the 10-17 expands my opportunities for creativity because it's so different than everything else in the bag. It's a serious photographic tool and a ton of fun, rolled up in one solid little package. The price is pretty good too.

Last edited by audiobomber; 10-17-2009 at 06:33 AM.
10-18-2009, 02:51 PM   #26
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Thanks to all who provided info...I bought my Pentax 10-17 mm Fisheye today. So far I'm very happy with this lens..it may replace my 16-45 as the reg. lens and the 16-45 will replace the kit 18-55 on my KM (K2000).
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