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03-29-2010, 07:59 AM   #1
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Wide angle on a budget

All and sundry:

I am looking for a cheap 2nd hand wide angle lens. Specs being:

- manual focus
- 12mm-16mm mark (zoom if cheaper?)
- to fit K10D
- readily available (ebay purchase)
- cheaper the better (!)

Idea being that I would like to mess around with such a specialist lens before committing to the premium that Pentax lenses demand, and hope to take some decent (but not catalogue) shots in the meantime.

I welcome your suggestions...


Last edited by sheylings; 03-29-2010 at 08:00 AM. Reason: updated wording
03-29-2010, 08:10 AM   #2
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Zenitar-K 16 f/2.8. It is a manual russian lens that is nominally a fisheye but less so on APS-C. You can use software like PTlens to de-fish it in post-processing and make it "rectilinear". This is probably your cheapest option; super wide-angle lenses just aren't cheap.

You will not find anything cheap in the 12-16 mm range that is rectilinear and manual focus, except maybe the Samyang 14/2.8 that is due out April. About $400 for that I believe. Remember that a full-frame rectilinear wide-angle is much harder to construct (requires more glass) than the equivalent lens for APS-C, so you're really better off buying a "digital" lens. There is no free digital lunch when it comes to ultra wide angles.

For example: in the history of photography there was only ever one 13mm lens for 35mm, it is a Nikon which would cost a five digit amount, if you found one, which you won't, since there were less than 350 produced. The widest rectilinear manual focus Pentax lens is 15mm, and that won't be cheap either.

So basically: Zenitar, and be prepared to de-fish, or suck it up and buy a modern autofocus DA lens.
03-29-2010, 08:13 AM   #3
emr
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Samyang is bringing soon a 14mm f/2.8 lens. I believe the price is still unknown, but it'll be most likely much cheaper than the same FL Pentax lens.

Also, you could get 16mm with the 16-45mm DA zoom which is (or at least was) reasonably priced.

I asked pretty much the same question recently:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/87005-any-bargain-wa-lenses.html

After a while I ended up getting a DA 15mm ltd but as it only came last week I haven't really managed to give it a try.
03-29-2010, 08:23 AM   #4
emr
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QuoteOriginally posted by emr Quote
Samyang is bringing soon a 14mm f/2.8 lens. I believe the price is still unknown, but it'll be most likely much cheaper than the same FL Pentax lens.
Actually it seems to be already out in the EU for 301€:

Samyang 14mm f/2.8 IF ED MC Aspherical Pentax - rezerwacja

EDIT: That store says "pre-order" and "on stock". Go figure. However, many people have happily ordered from that store incl. me (a Samyang 8mm FE).

03-29-2010, 08:26 AM   #5
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What do you want to photograph with the wide angle?
03-29-2010, 08:35 AM   #6
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Another sterling host of responses from PF users - thanks all.

@Eric - interesting to hear of the Aenitar - I'll look into that for sure. Similarly, the Samyang 14/2.8

@Joeyc - that idea is that I will be taking landscapes/ cityscape and action (mountain biking) shots with the lens.

Thanks again
03-29-2010, 08:51 AM   #7
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The reason I asked is that before I committed to the DA15, I actually used a Panasaurus head and stitched. The DA18-55 is pretty much distortion free by 22mm (33mm equiv.). Stitching together three or four images is pretty easy. Great for landscape and static images - doesn't work well for action or interiors. At under $100, it's a pretty nice solution if a wider perspective is your goal.

QuoteOriginally posted by sheylings Quote
Another sterling host of responses from PF users - thanks all.

@Eric - interesting to hear of the Aenitar - I'll look into that for sure. Similarly, the Samyang 14/2.8

@Joeyc - that idea is that I will be taking landscapes/ cityscape and action (mountain biking) shots with the lens.

Thanks again
03-29-2010, 12:33 PM   #8
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QuoteOriginally posted by sheylings Quote
@Eric - interesting to hear of the Aenitar - I'll look into that for sure. Similarly, the Samyang 14/2.8

@Joeyc - that idea is that I will be taking landscapes/ cityscape and action (mountain biking) shots with the lens.
Be aware that an ultrawide pushes away backgrounds. Your landscapes will look rather small. Ultrawides are for closing in on something and discarding the distance. The Zenitar, cheaper or better than alternatives, is actually quite decent when used right. For instance, if I know a bike will pass a certain spot, I would:

1) Enable Catch-In-Focus on my K20D;
2) Set shutter drive mode to Continuous;
3) Plug in wired remote;
4) Mount the Zenitar;
5) Place camera on tripod about 60-90cm (2-3 feet) from target spot;
6) Trigger the shutter;
7) Ride on by!

There are a couple of discussions going on here about ultrawides and fisheyes.

03-30-2010, 12:18 AM   #9
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@RioRico - interesting to hear you say that - my other post here is on just that topic!

You suggest in your post that you needn't be there holding the shutter button down - is this right?
03-30-2010, 12:58 AM   #10
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I'm gonna borrow this thread to ask a question about the Zenitar:

I've been wondering: if you use this 16mm fisheye lens on APS-C, and then de-fish it to rectilinear with PTlens, what's the equivalent angle of view/focal length? I.e, how wide would a rectilinear lens have to be to show the same scene? Anyone's done this math?
03-30-2010, 01:13 AM   #11
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The Tamron 17-50mm f/2.8 is probably a better option than the DA 16-45mm f/4. It's not too pricey either.
03-30-2010, 02:28 AM   #12
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QuoteOriginally posted by sheylings Quote
You suggest in your post that you needn't be there holding the shutter button down - is this right?
Oops, I was too brief. Wired remotes SHOULD have a latch that will hold the shutter open, like for B(ulb) mode. Yes, the shutter needs to be held open. I have read (but haven't tried yet) that a simple cheap 3.5mm audio plug (US$3 at Radio Shack, or you can cannibalize the plug from old headphones) with the connectors shorted-out with solder, and inserted into the remote jack, also serves to hold the shutter open. And there's always the DIY Pentax DSLR cable release, eh?

QuoteOriginally posted by Erik Quote
if you use this 16mm fisheye lens on APS-C, and then de-fish it to rectilinear with PTlens, what's the equivalent angle of view/focal length? I.e, how wide would a rectilinear lens have to be to show the same scene? Anyone's done this math?
Being an empirical kinda guy, I just ran a couple pictures through my favorite PP warez, PaintShopPro9, which has a distortion correction module licensed from PTlens. What I get is, a 180 degree DA10-17 image taken at 10mm defishes to a FOV of 125 degrees, and the ~108 degree Zenitar image taken at 16mm defishes to 75 degrees. The Zenitar's defished rectilinear equivalent would be 18.5mm.

BUT the aspect ratios change. The defished DA10-17 goes from 1.5:1 to 2:1, and the defished Zenitar goes from 1.5:1 to 1.64:1. And I'm not sure how to compare FOVs with different aspects. I think that's an apples-and-oranges comparison. An equivalent to the Zenitar would be to shoot with the kit at 18mm, then crop 8% from the top or bottom of the picture -- and now you've changed the FOV, which is based on the diagonal you've just shortened. Or it's like going from a 6x9cm MF camera to 6x10cm. Or something like that.

No, that can't be right. Because the DA10-17's FOV at 17mm is ~100 degrees, which is what the DA12-24's is at 12mm. Argh, I'm confusing myself. My trig is too rusty for this. IS THERE AN OPTICAL ENGINEER IN THE HOUSE?? He's around here somewhere...

Last edited by RioRico; 03-30-2010 at 02:53 AM.
03-30-2010, 06:41 AM   #13
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De-fished Zenitar

I have had a Zenitar 16mm for a few years and occasionally de-fish it with PTlens. As others have mentioned, the aspect ratio changes when you do this, but it's roughly equivalent to a 17mm to 18mm rectilinear in my experience.

Mike
03-30-2010, 09:05 AM   #14
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So uh, I guess I'm not gaining as much as I imagined I was, compared to the 18-55...
03-30-2010, 10:17 AM   #15
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QuoteOriginally posted by Erik Quote
So uh, I guess I'm not gaining as much as I imagined I was, compared to the 18-55...
[shrug] It depends on what you mean by 'gain'. Defishing and changing the aspect noticeably stretches the picture. Fishy or defished, you get huge DOF. That picture in my gallery if the flowers in a bowl on a porch railing, with the lawn chair fuzzy in the distance? That was wide open, in fading evening light, and the lens about 4 inches from the nearest flower. The chair was 25 feet away. I did everything to minimize DOF. That shot of the display cases? That took in a wall ~20 feet long, shot from the other side of the room 10 feet away. No way the 18-55 could have made the shot. Other pics I haven't posted yet were shot at f/4 and have DOF of about 1 foot to infinity. That's almost like using a radically tilted view cam -- or wide fast rectilinear glass that costs much more.

With the Zenitar as a fishy 16, slight changes in angle make a big difference in the picture. I tend to minimize the fishiness when shooting, avoiding stuff like having trees at the edges that all lean inward. But you can get massive distortion by having a close subject near one edge, and letting everything else get twisted around. Since the distance gets pushed away, it a good tool for separating subject from background.

And I now think I misinterpreted the numbers. The PTlens/defishing FOV number is misleading. The Zenitar's FOV is about 105 degrees, defished or not. To get 105 degrees with a rectilinear lens, it would have to be 11.5mm. The difference is that the rectilinear's aspect is 1.5:1 and the defished Zen's is 1.64:1. Even factoring in the wider aspect, the equivalent would still be around 12-13mm. So, try getting a rectilinear 12/2.8 for under US$200, eh?

Yeah, I was misled by the PSP2/PTlens FOV numbers. Defishing the DA10-17's wide 180-degree view DOESN'T narrow it to 125 degrees -- it's still 180. And defishing the Zen's 105 degrees DOESN'T narrow it to 75, it's still 105. Damn, I shouldn't believe everything I see on a computer.
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