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01-26-2013, 01:30 AM   #16
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QuoteOriginally posted by fb_penpho Quote
To me this demonstrates the assembly errors that can occur in an actual lens.
To me, it suggests that slicing a lens in half may cause some decentering.
At any rate, it probably voids the otherwise excellent Zeiss guarantee.

01-26-2013, 01:32 AM   #17
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Looking at it this way, i can't figure out how the focusing works.
They are alot more complex then I realized.
01-26-2013, 01:36 AM   #18
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QuoteOriginally posted by 7samurai Quote
Looking at it this way, i can't figure out how the focusing works.
Look for the brass bits in the middle of the lens.
They form the outer ring of the focusing helicoid,
and are attached to the external focus ring.
01-26-2013, 01:41 AM   #19
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QuoteOriginally posted by bullitt_60 Quote
Why are wide angle primes so expensive?
To add to what's already been said, I found a helpful explanation here:
lens - Why are wide-angle lenses so much more expensive? - Photography.

Here are some excerpts from the relevant post:


"But yes, in general wide angle lenses are expensive.

This is partially due to the design, and expectations placed on the lens. Any lens with a focal length shorter than the flange-focal distance (the distance from the back of the lens to the sensor, also called the registration distance, I think it's 42mm on a Canon) has to employ a retrofocal design, which basically means it's a normal lens with a reverse telephoto stuck on the back. The extra elements required adds to the cost and makes the lens more difficult to design and manufacture.

The other part of the problem stems from what you're asking the lens to do bend light from a huge number of different angles and focus it on a single rectangular plane. Any lens at the edge of the performance envelope, be it wide, long, aperture will be expensive. As different wavelengths of light bend at different rates you have to work very hard to avoid chromatic aberration where the constituent colours of light split up and fail to align on the sensor. Combating this requires aspherical elements. It's easy to grind glass into a sphere (simply spin it in front of a polisher) but to grind parabolic and other aspherical profiles is much harder (and therefore expensive). Wide angle designs also employs ultra-low dispersion glass for sharpness and contrast.

Telephotos can be just as expensive, but for different reasons. Light doesn't have to bend as far, so the design is simpler but this time the pure size of the glass elements required for a decent aperture (remember that f/2.8 means the [apparent] size of the aperture must be about one third of the focal length, which becomes really quite large once you go past 200mm or so) makes the elements expensive to produce (at this size dispersion & scattering is a big problem so UD glass and fluorite have to be used) and creates engineering difficulties in moving them around (motors and lens barrels have to be larger and stronger).

50mm is the sweet spot of lens design for 35mm SLRs, wide enough that the size of the elements required to maintain a wide aperture are still relatively small, but not so wide a retrofocal design is needed. This is why 50mm primes are such good value.
"

01-26-2013, 01:41 AM   #20
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QuoteOriginally posted by 7samurai Quote
They are a lot more complex then I realized.
This may answer OP's original question.
01-26-2013, 07:46 AM   #21
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QuoteOriginally posted by steve1307 Quote
When you take pictures with a wide angle you "get more stuff" in your photo, so its better value for your money . Those expensive telephotos only give you the little bit in the centre of what you're shooting.
lol, good stuff.

QuoteOriginally posted by lytrytyr Quote
Not a diagram, but this may give you an idea (Zeiss ZF18/3.5):
That's brilliant, thanks!

QuoteOriginally posted by Eulogy Quote
WHO DOES THAT TO A LENS! So cruel...for science?
Hopefully it was Zeiss themselves!

QuoteOriginally posted by all thumbs Quote
To add to what's already been said, I found a helpful explanation here:
lens - Why are wide-angle lenses so much more expensive? - Photography.
That's a good read, thanks!
01-26-2013, 07:54 AM   #22
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QuoteOriginally posted by Eulogy Quote
WHO DOES THAT TO A LENS! So cruel...for science?
That was actually informative...

This, not so much.

01-26-2013, 10:24 AM   #23
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QuoteOriginally posted by boriscleto Quote
That was actually informative...

This, not so much.

At least they weren't Pentax cameras!

01-26-2013, 04:13 PM   #24
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QuoteOriginally posted by lytrytyr Quote
At least they weren't Pentax cameras!
Yeah. They'dve broken the blender.
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