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Old Jul 28, 2010, 4:04 AM   #1
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Default which wide angle lens/prime without vignetting?

Hey all,
I know, that vignetting can't be avoided at some point, but I think I need something wider than my 24mm Vivitar prime. The kit lens already has some serious vignetting... so this is what I am looking for:

- wide angle prime (or zoom)
- as wide as possible, but at least better than my current 24mm
- can be fully manual, if it's A or F I won't say no
- no, almost no, just a little, barely notable, ... vignetting
- good quality, I don't mind it being a bit soft, as long as the detail can be recovered via postprocessing
- bonus1: fast/bright lens
- bonus2: close focus

I am using a Pentax DL2 at the moment and might upgrade to a K-x or something like that in the future. I was thinking of using an old full-format lens rather than a digitally optimized one and for now I am thinking in the $100-$200 range depending on quality for a manual lens, maybe more for a A or F one.

I followed this thread: http://forums.steves-digicams.com/pe...ome-range.html so I already got some ideas, but the vignetting problem wasn't discussed there and for me it doesn't have to be a zoom.

It would be nice if you could share your thoughts here, thanks in advance.

Th.
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Old Jul 28, 2010, 10:29 AM   #2
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For what I know about wide angle lenses, it's hard to get almost no vignetting.
I have the 18-55 kit lens and I must say I don'tnotice any disturbing vignetting, but maybe that is because I haven't really payed attention to it. That lens is a lot of bang for the bucks. So maybe you want to look into that one.
And check out some used ones on ebay, and then some reviews of wide angle lenses, most often they discuss vignetting as well.

Good luck
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Old Jul 28, 2010, 11:23 AM   #3
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Quote:
Originally Posted by JC de Jonge View Post
For what I know about wide angle lenses, it's hard to get almost no vignetting.
True, but less is better

Quote:
I have the 18-55 kit lens and I must say I don'tnotice any disturbing vignetting, but maybe that is because I haven't really payed attention to it. That lens is a lot of bang for the bucks. So maybe you want to look into that one.
Hm... I own that lens (see my 1st post) and my personal experience is so-so. Sometimes you barely notice it, but at other times it's disturbing. This review (http://www.photozone.de/pentax/135-p...report?start=1) has some more technical info on that. The kit lens is my widest at the moment so I mostly use it for the wide shots, maybe that's why I noticed it more than you. Overall the kit lens isn't that bad

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And check out some used ones on ebay, and then some reviews of wide angle lenses, most often they discuss vignetting as well.

Good luck
Thank you - let's see where this ends.

Th.
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Old Jul 28, 2010, 1:17 PM   #4
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With a rich blue sky in the background and good light the 18-55 will consistently give a darker blue on the edges than the middle. Removable in PP but annoying. Have you thought of a Vivitar 19mm prime. Could be what you are looking for.
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Old Jul 28, 2010, 11:01 PM   #5
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I haven't noticed vignetting with either the 18-55 or 18-250 on my K20D. I *do* notice sky-color differences in the corners, no matter what lens I use.

Wide primes: My M42 Lentar (Tokina) 21/3.8 cost all of US$23 including shipping. My PK Zenitar 16/2.8 cost a bit more, US$172. I use both these FF lenses a great deal, on both the dSLR and film cams. Then there's the DA10-17, but that's more of a problem, and costlier, and it's neither prime nor FF.

Some Russian and Nikkor glass around 20mm is available, fairly cheap. Yes, many Nikkors can be used on PK cams. I've dremeled protrusions off of some, and use others as-is, just force-fit onto the PK mount. All manual operation, of course.
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Last edited by RioRico; Jul 30, 2010 at 1:32 AM.
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Old Jul 29, 2010, 4:25 AM   #6
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@bigdawg
Hm... good point. I'll have a look into that one.

@RioRico
The Zenitar is a fish-eye, right? I'm not sure if that is what I want...

Thanks for the ideas so far.

Th.
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Old Jul 30, 2010, 2:00 AM   #7
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Quote:
Originally Posted by thkn777 View Post
@RioRico
The Zenitar is a fish-eye, right? I'm not sure if that is what I want...
The Zenitar is fishy, yes, but still quite useful. A rectilinear lens in that focal range will cost rather more. Wide (~20mm) Russian and off-brand rectilinear glass, like my Lentar-Tokina 21, can be found for rather less. For instance, here on eBay is a Pentax K-mount Soligor-badged version of my M42 Lentar. BIN, shipped in USA: under US$100. And this auction is for a Vivitar-badged M42 version, which will likely sell for around US$50-75. I'm quite happy with mine; slower means sharper. Happy hunting!
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Old Jul 30, 2010, 9:00 PM   #8
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Hi thkn777,

Consider that any FA or previous series lens was designed for a 36x24 film frame, so on an APS-C sensor, there shouldn't be any vignetting, no matter how wide you might go, even with standard thickness filters. Older lenses would be your best bet if vignetting bothers you a lot, I would think. The problem is that "FF" lenses shorter than 28mm were very much specialty lenses (consider that a 13mm lens on APS-C is equivalent in FOV to a 20mm on 135 film), and are more rare and expensive, especially the faster ones.

If you want the latest in digital coatings, SDM AF, Quick Shift or the newest grease, water, and abrasion resistant coatings, and wider rectilinear choices, you might be risking some darkening at the corners. There's always a tradeoff. Usually vignetting lessens as you stop down, so don't necessarily look only at the performance of the lens wide open for this particular "fault". Also, consider that you have to crop to print to any standard paper size, and you can PP to eliminate a lot of vignetting in many situations. Because of the "crop factor", you'll find a lot more "digital" lenses available in this class, and you might even find that they're less expensive (or at least a lot easier to find) for the angle of view they offer.

Personally, I find wide angle lenses hard to focus without AF (actually I find all lenses hard to focus without AF) so I'd go with the modern APS-C designed models (DA 12-24 would be my first choice, then the DA 16-45, then the DA*16-50 or Tamron 17-50/2.8, then the Sigma 10-20-- but that's me).

Scott
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Old Jul 31, 2010, 4:22 AM   #9
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Quote:
Originally Posted by snostorm View Post
Usually vignetting lessens as you stop down, so don't necessarily look only at the performance of the lens wide open for this particular "fault". Also, consider that you have to crop to print to any standard paper size, and you can PP to eliminate a lot of vignetting in many situations.
Uhoh,
thanks for reminding me... I might have tried to push things too much. Wide open (or almost wide open) shots in the evening to stitch some great panoramas, you know... I checked and it's these shots where vignetting bothers me the most.

Hm. That also explains why some images came out better than others. I knew that before - but I forgot.

Cropping is ok for printing from a single shot, but not for the panorama thingie. Hm, wait... why not?

...

I'll try something.

...

Be right back,
Th.

P.S. Oh... and the real wide lens is also because I am lazy at times and want to snap just 1-2 pics then move along.
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Old Jul 31, 2010, 10:52 AM   #10
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Morning,

Here is a good overview of what vignetting is, and the various causes.
Optical vignetting

This type of vignetting is caused by the physical dimensions of a multiple element lens. Rear elements are shaded by elements in front of them, which reduces the effective lens opening for off-axis incident light. The result is a gradual decrease in light intensity towards the image periphery [corners in particular, and edges in general]. Optical vignetting is sensitive to the lens aperture and can be completely cured by a reduction in aperture of 2-3 stops.
I have had some on my 18-55, but it has not really been severe. My 16-45 has had none, and neither has my 12-24. The 16-45 is running $200-$250 and is a very nice lens, very sharp, but it is much physically larger than the kit lens, and heavier. It also leaves a shadow in the bottom of a flash picture at 16mm when the lens is extended all the way out (its a reverse zoom - i.e., at 16mm it is zoomed out and at 45mm it is zoomed all the way in.).

In terms of primes and other lenses, its a matter of 1) finding them to buy, and 2) finding a writeup on them to see if they vignette. In the $100 to $200 for something less than 16 to 18mm, not a lot comes to mind. Pentax has some older primes. The best source of information on just what lenses were made is at...
In terms of the older lens' performance check here...
As you can see there is the 15 and 14, but not much else below 16.

Here is another database of both Pentax and non Pentax lenses (both primes and zooms)...
Tokina has a 17 in a Pentax K mount that is suppose to be superb. The problem is finding one. I have seen just a few available in the last couple of years.

Focal lengths less than 18 get expensive to design and build, plus the materials (lens) tend to be large and thus expensive too. Older lenses are full frame, and 18 was the equivalent of ultra wide angle today (considering the 1.5x crop factor). So all of the older lenses are in the 24 to 14mm range, and then there are the fish eyes, that is another post.

Then as you just discovered, there is stitching - which works real well, both hand-held and on a tripod.

... along the same lines, there is also a Pentax shift lens, that can be used for stitching also, in addition to perspective control. I just finally found one and am sending off a check today. I'll let you know how it works K 28mm f3.5 shift. I have had a couple of other opportunities, but they were way too expensive - and this is slightly more than what I wanted to pay but, the condition is great, lens perfect and for landscapes, I wanted to give it a try. This is probably my last lens, since I think that this covers everything I am interested in.
Hope that helps, and good hunting....

Last edited by interested_observer; Jul 31, 2010 at 11:03 AM.
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