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Messages - NormanBates

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46
Lenses / Re: Having fun with a couple of 100-years-old lenses
« on: January 21, 2013, 04:31:17 AM »
It is interesting to use old lenses like that.  That particular lens is a "Rapid Rectilinear" and was common on middle grade consumer cameras of the day. But the aperture is not calibrated in f/stops.  It is calibrated in what was called the "Uniform System".  In US stops US 16 equals f/16. US 8 is f/11; US 4 (your lens) is f/8 etc.

The system was adopted as a standard by the Photographic Society of Great Britain in the 1880's. Many less expensive Kodak lenses used the system until somewhere in the 1920's.

Thanks for the info!

Still impressive at f/8. Consider that this would be the center of a 4¼" x 3¼" piece of film. If it was a sensor with the pixel density of my NEX-5N, it would be a 108mm x 803mm sensor with nearly 400 Mpix! Take a picture with *that* and crop the center, and you get the image that I posted. Impressively sharp I say!

47
Lenses / Having fun with a couple of 100-years-old lenses
« on: January 20, 2013, 07:02:46 PM »


I've got a nice collection of very old cameras:
* Kodak 3 Folding Pocket Model G (USA, 1910)
* Kodak Vest Pocket (USA, 1913)
* Ernemann BOB OO (Germany, 1917)
* Kodak Retina 1 A (Germany, 1951)
* Taisei Koki Welmy SIX E (Japan, 1952)
* Kershaw King Penguin (England, 1953)

And I've done some lens whacking with a DSLR: you hold the lens in front of the camera, without attaching it, and shoot video like that, moving the lens forward and backards to focus, and tilting/shifting it by hand, letting light leak in through the sides, etc.

So, why not mix those two? I took the two cameras that will allow me to put my NEX-5N where the film usually goes (that would be the Kodak 3 G -pictured above- and the Ernemann BOB OO), took away the back side, and placed them safely on a bench or similar. Then I took my Sony NEX-5N, took the lens away, and manually held it inside the bellows camera, looking at the screen while moving around the NEX in order to get good focus and take a still.

You can see the results here:
http://www.similaar.com/foto/oldcam/oldcam.html

My take: they look so good that it doesn't even feel that they were shot with such old lenses! (specially the Kodak: click on the first image to see it at full resolution: that 100-years-old f/4 prime is surprisingly sharp!)

48
Lenses / Re: Tokina 11-16 f/2.8 on full frame: it's actually quite good!
« on: January 20, 2013, 02:14:55 PM »
old version

49
Wow, you're a tough crowd to please!

I'm very happy with the results I got. Given how I use my camera, I don't need further testing.

50
Lenses / Re: Tokina 11-16 f/2.8 on full frame: it's actually quite good!
« on: January 20, 2013, 12:26:21 PM »
The camera was borrowed, I'm just pondering the fullframe move and I wanted to see how well my lenses would work with the bigger sensor. But now that the owner knows it works so well (he had disregarded it as "probably too soft in the corners") there should be some pics to show if he finds a situation where such a wide angle lens is needed.

51
Indeed, if you keep lens and distance constant, APS-C will give you lots more detail. Because it's just as if you had a 50 Mpix full frame body and cropped the center of the image.

But that's not my usual scenario. For me, the right comparison is "Elmarit-R 35mm f/2.8 on APS-C set at f/2.8" vs "Summilux-R 50mm f/1.4 on full frame set at f/4.5". Similar FoV, similar DoF --> full frame is clearly sharper.

As I said, if this is not the way you shoot, run your own tests designed for your usual scenario (actually, you should run them anyway!).

52
Lenses / Re: Tokina 11-16 f/2.8 on full frame: it's actually quite good!
« on: January 20, 2013, 11:48:54 AM »
Not really worried about that. I'm in Europe, and those two halves are glued on vinyl then stuck on a door. Plus, at $1, that's the cheapest resolution test chart ever!

53
Lenses / Re: Tokina 11-16 f/2.8 on full frame: it's actually quite good!
« on: January 20, 2013, 10:19:15 AM »
on a side note: When you tear a banknote apart, make sure one part is doubtlessly bigger than half a note.

Just curious: why?

54
No surprise there.  But just want to point out, this is a DxO-like conclusion.  You used a 5DII for the test, I can say from experience that in many situations, the APS-C sensor in my 7D delivered sharper pictures than my 5DII, by virtue of its better AF system.

Indeed. You may also notice that I listed my best 3 lenses there, and none of them has AF.

Nearly everything on that site was created because I needed it, including these tests. They're made for me, and designed for my very special needs.
Everybody should test their equipment to see how well it fits their needs, what can be done and what's not a good idea, and where there's room for improvement. I'm just sharing my results. They shouldn't stop anybody else from running their own tests.

55
What I mean is that you've got an image circle, a bunch of photons that are projected back by the lens. This is anlogue. You put the same ~20 million photosites behind that in both cases, but on APS-C each of them is smaller.

If you want to think it like this, it's as if, instead of a ~20 Mpix full frame sensor, you had a ~50 Mpix full frame sensor, and then you used only the central portion, and enlarged it so that it is now the full image (and this is where my "magnyfy issues" argument comes in: you are enlarging the image, and this magnifies any defects in the lens).

So, yes, as you say, the thing is that the pixels are smaller, and this reduces quality.

In any case, the proof is in the pudding: fullframe gives a lot more detail.

56
I have to decide between APS-C and full frame, and one of the things to look at is sharpness.

With APS-C, as opposed to full frame, you're only using the central portion of the image circle, the sweet spot: you're not using those blurry corners, and this should lead to sharper pictures. On the other hand, because the sensor is smaller but final image resolution is the same, you're blowing up the analog image that the lens projects on the sensor; this is bad, because every defect will be magnified. Which force is bigger?

I ran some tests trying to find out, shooting stills with a 5D2.

My conclusion: as a general rule, a lens will always be sharper on full frame than on APS-C, both in the center and in the corners.

You can see the tests and read a bit more about them here:
http://www.similaar.com/foto/lenstestsff/lenstestsff.html

57
Lenses / Tokina 11-16 f/2.8 on full frame: it's actually quite good!
« on: January 20, 2013, 06:10:15 AM »
Not only does it work on full frame (as a 15-16mm f/2.8, unless you want a hard vignette in your image), but it is actually pretty sharp!

Check my tests here:
http://www.similaar.com/foto/lenstestsff/lenstestsa.html

My test chart is not huge, so with such a wide angle lens this is a very short focus test. In these conditions, it's not the sharpest lens in the test, but even in the extreme corners it is better, for example, than the Canon 24mm f/2.8, and similar to many other lenses, including my beloved 35mm f/2.8 (which I regard as a very sharp lens even in the corners).

Trouble is, a lens can be very sharp when focusing one foot away, but blurry when you focus at infinity. I'll have to test the Tokina in the field, but based on these results, I'm already quite impressed. If it keeps its sharpness when focused at infinity, this may be the best bang-for-buck 16mm f/2.8 prime you can buy for a full frame camera.

58
EOS Bodies - For Video / Re: Inside the Canon EOS-1D C
« on: January 09, 2013, 01:04:53 PM »
4K video should not cost that much!

And it won't. It's just that it won't be Canon selling the cameras.

59
EOS Bodies - For Video / Re: Inside the Canon EOS-1D C
« on: January 09, 2013, 04:13:34 AM »
Fair or not, this "same hardware at twice the price" thing is not going to earn them a lot of sympathy

60
Portrait / Re: Food pics - help required
« on: December 19, 2012, 06:08:29 AM »
Another fast "product photography" tutorial:

Better Product Shots Small | Large

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