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02-18-2010, 09:12 AM   #1
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Why no CHEAP wide angle lenses?

Alright I am a noob but hear me out. I bought a Pentax k-x kit with 18-55mm and 55-300mm zoom ~$650. Then I went on ebay and for ~$50 picked up a 50mm f1.4 prime lens. Now I feel like I have all the lenses I need (at least for many years until I am more pro and have more money to justify on fancier equipment), but I would love to have a wide angle lens in the 10mm to 12mm range. But old wide angle lenses are useless because of the crop factor.. and the cheapest wide angle lenses are about $500. Well I am only about $700 in on equipment so far including the body so that seems like a lot of money! Why would it be so difficult to build something cheaper? I mean the kit lens at 18mm will probably remain the widest thing in my kit, and that probably costs $50 for Pentax to produce. Obviously the kit lens is so mass produced. But seriously I want a sub $200 wide angle, it doesn't have to be top quality but not some zenitar cropped fish-eye. Should I just suck it up and work harder to earn more money because wide angle lenses inherently cost a lot to produce? Or is this some type of conspiracy?

02-18-2010, 09:23 AM   #2
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I'll let others with more expertise expound on this, but wide angle lenses for APS-C are shorter focal lengths and seem to be more challenging to design.
02-18-2010, 09:32 AM   #3
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More glass, more aberrations, tougher lenses to design. More raw materials needed, more time to manufacture, more risks to screw things up. Less demand, too, except for higher quality versions. All those things build up to draw the price up.
02-18-2010, 09:54 AM   #4
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One problem is, lenses worth owning are almost always expensive, relative to the cost of the camera.

The other problem is using a mount designed for film. Everything works out so a lens around 50mm can be fast and cheap, which made sense because everyone wanted a 50mm normal lens. On film, 24mm was getting very wide-angle, and wider than that was very specialized. Not many of these older lenses were that great by modern standards, sacrificing quality for their extreme wide-angle field of view.

DSLRs use the same mount so we have access to lots of old lenses, but few old ones worth pursuing. Sensors work differently than film so new designs work better anyway. With the sensor size, the 50mm sweet spot for fast, cheap and excellent lenses is not as useful any more. Design and manufacturing improvements have made the lenses better, but it's still a lot of work to make a 10mm rectilinear lens. A lens that's just 1mm wider in this region is noticeably wider in use.

At this point, "suck it up" is the best advice. One way to solve this is to have a larger sensor. The large-sensor cameras are still around $2000, which isn't going to save you any money; it'll just make a $500 lens seem a little cheaper by comparison.

02-18-2010, 09:55 AM   #5
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Quality lenses are hard to make and can take up to 6 week to make one lens. Specialyl when you take in mind the design, abbriviations, clarity, fringing, distortions reflections, flares and on............

Check this video from the discovery channel to get an idea on how lenses are made.

[YT]http://www.youtube.com/watch?v=X7_wL0ZZi6k[/YT]
02-18-2010, 10:09 AM   #6
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Wide angle lenses are actually much much harder to design than telephotos. You have to understand that a wide angle lens has to bend light at pretty sever angles and redirect it in an orderly fasion onto a flat plane (your sensor). This is much more dificult than capturing relatively straight-on light and just funneling it to the sensor. Frankly its amazing that lenses like the 18-55mm kit lens cost as little as they do and yet still perform adequately.

Mike

p.s. don't fall in to the trap of comparing DSLR wide angle lenses to the "wide angle" lenses in P&S cameras. Much easier to design a lens that covers a sensor the size of a pencil eraser rather than a lens that covers a postage stamp sized sensor... and it gets even harder the larger the sensor gets...
02-18-2010, 10:18 AM   #7
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since no one has answered this directly, I will attempt to in simple terms.

It all starts with the size of the camera and the registry distance. (i.e. the distance from the lens mount to the film/sensor plane). On pentax this is about 46 mm and is in the same order of magnitude +/-3-4mm for all SLR makers.

This space is needed to allow the mirror to swing , etc.

as a result, the optical design becomes quite difficult and lens complexity increases to make a lens with an "effective focal length" less than about 50mm because the effective focal length becomes smaller than the distance to the sensor from the mount.

the shorter the lens the more expensive.

the crop factor has not helped this, because of the change in effective field of view. WHile there are a lot of good and inexpensive 24 and especially 28 and 35 mm lenses available they are no longer wide enough.

If you truely want to go ultra wide, there are 2 options, either a good prime, or one of 3 ultra wide zooms (Sigma 10-20, pentax 12-24 or tamron 10-24)

there is also the option of going with a fisheye, either like the 10-17 zoom, or one of the samyang, Bower, vivitar et. al. 7-8mm lenses. yoou can, with imaging software streighten the fisheye effect anyway. These lenses are MF but KA mount so all auto exposure functions work, and they are in the $280-$370 range

02-18-2010, 10:26 AM   #8
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some good points above.
My advice? Look into used DA16-45, or even new one.
Those 2mm will make pretty significant difference in FOV and it's the best value for the money if you don't really feel like splashing out but yet want more than 18mm.
If you really want wide, than Sigma 10-20/4-5.6 is terriffic lens at less than 1/2 price of DA12-24 (at least in UK).

BR
Peter
02-18-2010, 12:00 PM   #9
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you can buy cheaper ultrawide zoom lenses. you just need to buy used ones for less money than what you spend on a brand new. some usually sells for $300-$400 on average, except the DA12-24 which more or less retain their value at $600-$650. or you could settle for much less wide but good enough for wide use like the DA16-45 which only costs at around $200-$250 used. or $300 brandnew. although some sellers sell it brand new for around $350 and even up to $650 (shipping included) which IMO, is quite over the top.

Last edited by Pentaxor; 02-18-2010 at 01:13 PM.
02-18-2010, 01:09 PM   #10
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Thanks for all the info guys! Sounds like a wide angle lens is a difficult engineering feat! One other thing that occured to me is that mainstream APS-C DSLRs have only been around for a few years. And the film lenses made most obsolete by DSLRs are wide angles lenses. So DSLR wide angles are high demmand (since old ones don't work) and low supply (since they have only been sold for a few years).
02-18-2010, 02:47 PM   #11
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QuoteOriginally posted by bigjonnee Quote
...snip.... One other thing that occured to me is that mainstream APS-C DSLRs have only been around for a few years. And the film lenses made most obsolete by DSLRs are wide angles lenses. ...snip... (since old ones don't work) ...snip....
say what?
Film lenses are made obsolete by DSLR and they don't work?????
Well, they do work, and AFAIK they are still valuable. The new lenses are (most probably) better corrected for CAs and PFs (although even venerable 12-24 gets a purple "blush" at times).
And the film lenses are enjoying the sweet spot advantage with APSC sensors which may give them advantage with regards to distortion, and corner sharpness!
And because Pentax didn't exactly make many UWAs (correct me if I'm wrong, but there were only K15, K18, A15 [only handfull] and than only 20mms or FEs) and they are quite a chunks of glass they are fairly costly!
So, don't get me wrong but I think that those two assumptions you made there are simply wrong.

BR
Peter
02-18-2010, 03:44 PM   #12
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I realize "it works" I just mean to say that a wide angle film lens is no longer so wide on a dslr as in it doesn't work to take such a wide angle feild of view photograph. So if you really want a functional wide angle lens to use on your dslr you need a new one designed for apsr.
02-18-2010, 03:52 PM   #13
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Lenses that wide weren't cheap for 35mm format either. APS-C versus 35mm barely enters into it. But my question would be, what experience do you have that convinces you that you want something in the 10-12mm range on APS-C? Were you accustomed to using 15-18mm lenses on film? What I'm getting at is, how do you know 14, 15, or even 16mm wouldn't be enough for your purposes?
02-18-2010, 04:06 PM   #14
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16mm is wide enough

.

Yes, I think a contrasty, sharp zoom that gets out to 16mm would be 1) wide enough on aps-c for most WA applications, and 2) great if it could be had for $250 or less used.

Too bad something like that doesn't exist.

Oh, wait!



(DA 16-45 f/4)


Stopped down, the DA 16-45 is a very good WA tool and is basically a great value any way you add it up.


.

Last edited by jsherman999; 02-18-2010 at 04:14 PM.
02-18-2010, 04:09 PM   #15
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marc raises a good point.

I can't obviously speak for the OP, but form my own experience, when I shot film, the widest I had was a 24mm and I was frustrated that it was not wide enough. That is equivelent in todays world to a 16mm on ASP-C.

when I got my *istD, I took the FA-J 18-35 that came with it and used that on my PZ-1 for wide shots.

I finally was approaching what I wanted, so for the complete move to digital I went for a sigma 10-20. Still shoot 60% of all shots with that lens at 10mm. Now I'm looking at an 8mm fisheye
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