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08-03-2010, 10:09 PM   #16
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QuoteOriginally posted by CWyatt Quote
Not sure about the later versions but my mark i DA18-55mm was pretty ugly at 18mm at any f-stop, let alone at f/3.5.
Later versions *are* quite a bit better. But FWIW, photozone isn't as unimpressed even with the original. Extreme corners are the weakest link, but probably no worse than a typical 28mm lens on FF.

08-03-2010, 10:31 PM   #17
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Those are some good suggestions.

I think the film camera one might be the simplest, and WHY DIDN'T I THINK OF THAT (answer: my age). I'm going to begin looking into some film bodies - I know I can find those things anywhere for a song.

Any other models I should look out for?

As for the lens suggestions - I am VERY intrigued by your suggestion to operate on the nikkor lens.

Any good guide out there on how to do that sort of thing?

And, while I love the fact that my kit lens allows me to go to 18mm, the corners are pretty terrible at f9. I would be willing to pay for an upgrade (and I know they exist because I've seen other people's pictures )

If I can find a good way to shoot the pictures I want to shoot without waiting 5 years for an afforadable full frame, I am all ears.
08-04-2010, 09:04 AM   #18
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QuoteOriginally posted by paperbag846 Quote
I think the film camera one might be the simplest, and WHY DIDN'T I THINK OF THAT (answer: my age). I'm going to begin looking into some film bodies - I know I can find those things anywhere for a song.
True - but now instead of spending money on the lens, you'll spend it on film and developing. By the time you've taken a few hundred shots, you'll have spend more than you would have on wide angle lens for digital.

Not that film isn't wonderful in its own right - but if you're thinking of this as a way to avoid the high cost of wide angle lenses for digital, you've kind of got that backwards.

QuoteQuote:
And, while I love the fact that my kit lens allows me to go to 18mm, the corners are pretty terrible at f9.
The current versions of the kit lens? While corners are never as good as centers, they shouldn't be "terrible", especially at that aperture. Of course, you do have to make sure they are in focus, which is not very common when shooting wide angle. You might want to post some sample pictures that demonstrate what you are unhappy with.

In any case, as I said, most affordable (or even not-so-affordable) 28mm primes will be no better in this regard on film. Only advantage will be that you won't be tempted to pixel peep so much and may not notice.
08-04-2010, 10:08 AM   #19
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QuoteOriginally posted by Marc Sabatella Quote
The current versions of the kit lens? While corners are never as good as centers, they shouldn't be "terrible", especially at that aperture. Of course, you do have to make sure they are in focus, which is not very common when shooting wide angle. You might want to post some sample pictures that demonstrate what you are unhappy with.
You know, the focus might be the issue. I have the 18-55 II. I don't suspect that OOF would be superb on this lens at f9.

I am very happy with my kit lens, all in all, but I suppose I just assumed that with the jump in IQ i noticed with my SMC A 28 2.8 and SMC 55 1.8, that I would get the same with an 18mm ish prime. I guess I just have to come to terms with the fact that what I'm after is specialty and I need to fork over specialty prices.

The other issue might be pixel peeping .

PS: I normally crop this photo, but I'm showing the unaltered DNG so we can see the extreme corners.

18mm 1/200 ISO 200 f9


Last edited by paperbag846; 10-27-2010 at 11:55 AM.
08-04-2010, 10:26 AM   #20
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QuoteOriginally posted by paperbag846 Quote
I am VERY intrigued by your suggestion to operate on the nikkor lens. Any good guide out there on how to do that sort of thing?
A few web pages can be found showing various conversions, often involving replacing the NI with PK mount, maybe with some work to maintain aperture automation; but I can describe a simple dremel operation producing a totally manual lens.
_ _ _ _ _

First, I'm not familiar with the differences between the pre-AI, AI, AI-S, whatever other F-mounts exist, but they seem minor. Even an AF mount can probably be modded successfully.

Next, I use a few manual F-mounts, two of which I have modded, the others not. On the mount, the aperture ring (bearing the coupling nose that sticks out) is next to the lens base, with an extension that runs partly or completely around its perimeter. The keeps the NI base from making a snug fit to the PK mount.

On some lenses, Tokinas badged as Soligor and Lentar, the extension runs all the way around the aperture ring's circumference. It's impractical to cut that off for a tight fit, so I just force-fit those lenses onto my K20D. Haven't lost one yet!

On the lenses I modded, a Nikkor and a Tokina RMC, that aperture-ring protrusion is reduced to one short arc and a nub, which are easily excised with a Dremel Reinforced Cut-Off Wheel #426. I perform surgery on the wood railing of my back porch. Steps:
* Remove the base (don't lose the screws).
* Pull off the aperture ring and position it for cutting.
* Trim away the protrusions so the bottom of the aperture ring is flat.
* Dust everything off and replace the aperture ring and base. Voila!
My Nikkor and Tokina RMC had a couple linkage flags hanging down; the longer flag might get in the way, so I removed those too. That may be unnecessary. My Soligor and Lentar, and an Albinar-Tokina without the full-circle skirt, have either one or zero short linkage flags -- nothing to cut off. The basic rule here is: Check how the mount fits before removing stuff. I have a PK macro tube that I use as a test mount for lens work.
_ _ _ _ _

Anyway, the modded lenses work fine; the aperture rings turn smoothly, but with no f-stop detents. The bases fit snug on the PK mount, shorting the K20D's signal pins so they can be used with Catch-In-Focus. They show no tendency to fall off the camera. As with any experimental surgery, it's best to practice on a cheap sacrificial lens. Instead, I went straight ahead on my prized Nikkor 85/2, and managed not to f*ck it up despite my mechanical ineptitude. I'm a software guy.
Q: How many computer programmers does it take to change a light bulb?
A: None -- that's a hardware problem.
Have fun with a Nikon conversion! My current project: chopping the OM mount on a Vivitar prime to fit my K20D. It snaps right onto my ZX-M -- why not the digital??
08-04-2010, 10:34 AM   #21
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Original 10-20 Sigma is fine for my purposes although 2.8 would be better for basic tourist stuff in large and/or old buildings. Maybe a Samyang 14 mm would be helpful but I wouldn't get it out but a handful of times each year. If that.

I get more use from the long end. Not sure how much I'd have to invest in FF lenses to match my Sigma 18-250 or 100-300 f/4. I don't want to think about it.

No opinion here, just a description of my use.
08-04-2010, 10:43 AM   #22
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QuoteOriginally posted by glanglois Quote

I get more use from the long end. Not sure how much I'd have to invest in FF lenses to match my Sigma 18-250 or 100-300 f/4. I don't want to think about it.

.

Tamron AF 28-300mm f3.5-6.3 XR Di LD IF Makroca. 299,00
Sigma APO 120-400mm f4.5-5.6 DG OS HSM ca 680
08-04-2010, 11:27 AM   #23
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I just wanted to tell you that i bought a Walimex 8mm a while ago for $280. But checking on ebay, wow, they got expensive. They sell at $484 right now

Walimex Pro 8mm/F 3.5 FishEye lens for pentax PK mount - eBay (item 230458276998 end time Sep-01-10 21:00:52 PDT)

Of course it are MF lenses, but they are very good lenses for the money

08-04-2010, 07:59 PM   #24
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QuoteOriginally posted by paperbag846 Quote
You know, the focus might be the issue.
Seems to be here. Unless you went out of your way to focus at the very bottom of the picture, the cropped area would be well in front of the focus plane.

But even though I'd say that with focus directly on that plane it will look better, this still isn't what I'd call "terrible" considering what we're looking at. Yes, the A28/2.8 looks better in the corners - on APS-C, where the lens' actual corners are lost to the crop so you're really seeing only the center portion of the image. Stick that 28 on film, blow the image up as large as you did here (viewing a 10MP image on screen at 100% is the equivalent of a 30x45" inch print or so!), and *then* examine the corners (the parts that are cropped out on your DSLR). I seriously doubt it will look better that the above corner crop from the DA18-55II - very likely not even as good.

QuoteQuote:
I am very happy with my kit lens, all in all, but I suppose I just assumed that with the jump in IQ i noticed with my SMC A 28 2.8 and SMC 55 1.8, that I would get the same with an 18mm ish prime.
Well, an 18mm prime made for film would have its corners cropped out too, so yeah, I'd expect them to look a bit better. Although maybe not - on the whole one wouldn't expect an 18mm prime for film to be *nearly* as good as a 28mm prime, simply because they're so much harder to make. But FWIW, I can confirm the DA15 *does* look better in the corners at that aperture when they are in focus.
08-04-2010, 08:52 PM   #25
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QuoteOriginally posted by glanglois Quote
Not sure how much I'd have to invest in FF lenses to match my Sigma 18-250 or 100-300 f/4. I don't want to think about it.
The Sigma 100-300mm f/4 is full frame?
08-04-2010, 09:22 PM   #26
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QuoteOriginally posted by Marc Sabatella Quote
But even though I'd say that with focus directly on that plane it will look better, this still isn't what I'd call "terrible" considering what we're looking at.
Thank you so much for your help - very informative. The more I think about it, the less I think of this lens / ASP-C being an issue.

Now for a photographic question - in this scene I focused on the horizon because I wanted to get those two buildings as sharp as possible.

Would there be a way to get both the foreground and the buildings in focus? I've tried "hyperfocal" focusing but I can never seem to get it to work. For the most part, focusing to infinity seems to be the only way to get the distance as sharp as it can be.

Would my only real option here be to stop the lens down to something like f16? Now I'm worried about diffraction..!

OOOOOOO it's a hard life .
08-04-2010, 09:41 PM   #27
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I would assume that Pentax will have to introduce a FF camera into the game at some point to stay in the camera race at all. This is nothing against Pentax...I'm just basing this off of Nikon's introduction of the FF camera after basically saying that it was all hype. They couldn't let the 5D kick the crap out of them, so they brought out some FF. Now they have the D700, which is my favorite FF camera.
08-04-2010, 09:41 PM   #28
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Yes

QuoteOriginally posted by CWyatt Quote
The Sigma 100-300mm f/4 is full frame?
But it would need to be replaced by a 150-450mm f/4. Just got back from a major aviation event. I used every bit of that reach and could have used more to get the shots I wanted without serious cropping. F/4 allowed decent shutter speed - another requirement for a guy with a less-than-steady grip.

The 100-300mm was just on the edge of too heavy to use handheld - a requirement for certain aerial shots.

We'll see what the next year brings ....
08-04-2010, 11:49 PM   #29
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back to wide angles...

How to get a wider-angle image:

* stitch
* move back
* get a FF camera
* get a wide adapter
* get a wide lens
* get a fisheye
* don't
08-05-2010, 12:07 AM   #30
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QuoteOriginally posted by glanglois Quote
But it would need to be replaced by a 150-450mm f/4.
Not necessarily, full-frame might give you the resolution to crop more tightly, which is essentially what the APS-C is doing with your full-frame lens anyway.
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