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About This Page: This is a discussion on Computers/Tech/Photo within the LetsGoKings.com forums, at Los Angeles Kings Hockey Fan Forum. Originally Posted by BleedingPurple
That's crazy! Very cool stuff. Any way you could take a photo of this rig all put together?
Yeah. Gimme a bit.
Originally Posted by BleedingPurple
That's crazy! Very cool stuff. Any way you could take a photo of this rig all put together?
Yeah. Gimme a bit.
Quote:
Originally Posted by BleedingPurple
I was wondering about the focus of some of the photos. It seems the very center (obviously) is always in focus but outer edges that appear to be in the same vacinity are out of focus.
For example, the top head of the nail;, the center 50% horizontally is in focus but the upper and lower 25% horizontally is out of focus even though they are very close in proximity.
Well, if you think of the focus point as being a flat plane parallel to the front of the camera on which anything is in focus, then you can see why only the middle of the head of the nail is in focus. It passes through the focal plane at an angle because I took the image with the camera pointed down at the nail from an angle of approximately 45-degrees.
Had the sun not been behind a cloud, the f-stop might have been a little higher (tighter aperture, greater DOF) so more of the nail would have been in focus. I'm still learning how to control DOF with these things installed.
__________________ VOTE Tarquin Fin-tim-lim-bim-lim-bin-bim-bin-bim Bus Stop F'tang F'tang Olé Biscuitbarrel IN 2008!!
I just stuck the big mama-jama 70-200 f/2.8 on the end of the stack of tubes. At 200mm, the focus point is like eight inches in front of the lens! Normal minimum focusing distance is like 5 feet!
But the funny thing was that at 70mm, the focus point is somewhere between the front lens element and the UV filter!! I can probably focus on the fingerprints on the UV filter!!
__________________ VOTE Tarquin Fin-tim-lim-bim-lim-bin-bim-bin-bim Bus Stop F'tang F'tang Olé Biscuitbarrel IN 2008!!
Very interesting. Are these tubes a cheaper alternative to a very expensive lens or is the application totally different?
I guess they essentially allow you to turn a regular lens into a macro lens. Even so, macro lenses won't get you much closer in terms of minimum focusing distance, or much bigger in terms of magnification ratios.
For instance, the AF Micro-NIKKOR 60mm f/2.8D has a minimum focusing distance of 8.75 inches. I can get within 1" of my subjects with all these tubes behind my 50mm f/1.4 lens. And (according to the tables supplied with the tubes) the image will have greater magnification ratio with the tubes (1.5:1 with all the tubes on). Most macro lenses get 1:1 ratios.
There are advantages to longer focusing distances for 1:1 magnification. Photographing poisonous things? Yeah, I'd want at least a foot between that spider and me! But you can get the increased minimum focusing distance with tubes, as well! Just put them on a longer focal-length lens!
__________________ VOTE Tarquin Fin-tim-lim-bim-lim-bin-bim-bin-bim Bus Stop F'tang F'tang Olé Biscuitbarrel IN 2008!!
Last edited by FlyBoeingJets; January 9th, 2008 at 03:41 PM.
For instance, the AF Micro-NIKKOR 60mm f/2.8D has a minimum focusing distance of 8.75 inches. I can get within 1" of my subjects with all these tubes behind my 50mm f/1.4 lens. And (according to the tables supplied with the tubes) the image will have greater magnification ratio with the tubes (1.5:1 with all the tubes on). Most macro lenses get 1:1 ratios.
There are advantages to longer focusing distances for 1:1 magnification. Photographing poisonous things? Yeah, I'd want at least a foot between that spider and me!
I think both have advantages and disadvantages. I have the 60mm Micro. That 8.75" number is from the film plane. The minimum distance from the front of the lens is like 2.75" with a 1:1 ratio on a 35mm size sensor. On a DSLR it would be 1.5:1. The good thing about it is that it is sharp, compact and versitile. You are right about working distance being important though It is not easy to get so close sometimes, and it is even harder to light the subject properly when you are right on top of it. So generally I don't use the 60 for macro work. I also have the 105mm micro and use that for my close up work becase it gives me the same enlargement ratio but at a working distance of 9" or so. Problem is that it is kind of a big lens, especially the newer VR version that I have. Very sharp lens but big and heavy. I think I use it most often for copying photos on a copy stand when I don't have the time to scan them.
I think both have advantages and disadvantages. I have the 60mm Micro. That 8.75" number is from the film plane. The minimum distance from the front of the lens is like 2.75" with a 1:1 ratio on a 35mm size sensor. On a DSLR it would be 1.5:1. The good thing about it is that it is sharp, compact and versitile. You are right about working distance being important though It is not easy to get so close sometimes, and it is even harder to light the subject properly when you are right on top of it. So generally I don't use the 60 for macro work. I also have the 105mm micro and use that for my close up work becase it gives me the same enlargement ratio but at a working distance of 9" or so. Problem is that it is kind of a big lens, especially the newer VR version that I have. Very sharp lens but big and heavy. I think I use it most often for copying photos on a copy stand when I don't have the time to scan them.
Okay. There's some good info that's new to me! I didn't know that minimum focusing distance were measured from the sensor, though to think about it now it really only makes all the sense in the world. Thanks DeaderFan!
So what is my 1.5:1 ratio from the table that was included with my tubes on my DX sensor? Is it 2.25:1? Couldn't be! Or could it?
__________________ VOTE Tarquin Fin-tim-lim-bim-lim-bin-bim-bin-bim Bus Stop F'tang F'tang Olé Biscuitbarrel IN 2008!!
FlyBoeingJets
