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5
votes
2answers
203 views

How do zoom, magnification, and focal length relate?

Zoom lenses and cameras with superzooms are often sold with a times ("×") zoom number — like a 12x zoom or 30x zoom. The question How do I convert lens focal length (mm) to x-times optical zoom? ...
1
vote
1answer
62 views

Can I make a 1:2 macro lens into 1:1 true macro using only bellows?

I have a Tamron 90mm with a 1:2 magnification. If I use a bellows will that make it 1:1? I know I can buy an extension but I also what to know if I can get 1:1 magnification with only the bellows ...
0
votes
0answers
96 views

How to get width and height of an image based on distance

I have an app to overlay the images on the camera overlay. But I need to set the width and height of the image based on the user distance. If the distance is, say 8 feet, how can I calculate the width ...
2
votes
1answer
113 views

How to find numerical aperture of lens

I need to find the precise collection cone angle of an arbitrary objective at an arbitrary (but known and finite) object-side focal length. This is typically given as the "numerical aperture", defined ...
1
vote
1answer
509 views

How do I set the manual focus magnification on the Sony NEX-5R?

The NEX-5R has a manual assist function: if you enable it, and put the camera in manual focus mode, then when you rotate the focus ring, the camera shows a magnified view so that you can focus better. ...
1
vote
3answers
1k views

Is the formula for object image size given focal length, etc. independent of sensor size?

I am trying to figure out how big an object of, say, 50cm height at 100m distance and 600mm focal length would appear on a camera's sensor. The ubiquitous formula object size in image = focal length ...
0
votes
1answer
132 views

What focal length and quality of lens do I need to read 15cm high text at 500m away? [duplicate]

I have to photograph 15cm high printed text from 500 meters away. The text has to be human readable in the result. What kind of focal length do I need? Can i compromise, and get a camera with less ...
3
votes
1answer
142 views

What is Effective Aperture?

What is Effective Aperture? And how it can affect my exposure? Also how does it relate to magnification? A question that talks about effective aperture but without details
0
votes
1answer
174 views

Compare magnification of point and shoot cameras with dSLR telephoto lenses [duplicate]

I just want to know how much magnification there is... if I have a point and shoot camera and it has 10X zoom, I'm seeing that the subject is "brought" 10x closer. So, what does a dSLR telephoto lens ...
-1
votes
1answer
684 views

How to calculate the magnification factor of an object to its image?

I have an object of size 37.5um x 37.5um, and captured a 640 x 480 resolution image of the object with a CMOS sensor. I see that the object is around 200 x 200 pixels in the image. How do I calculate ...
2
votes
1answer
204 views

What's the magnification of a full frame macro lens on a MFT camera?

I think I've got this right but I would like to be positive before I buy a lens. If I were to use a Nikkor 55mm full frame macro lens with a 1:2 magnification and a 9inch min focus on a micro four ...
3
votes
1answer
187 views

Can I make my Canon dslr instantly zoom to 1:1 after shooting a picture?

When you shoot a photo, your picture is displayed onscreen. It's said to be possible to zoom in the picture, but pressing the zoom buttons do not zoom but activate their second function. So is it ...
2
votes
1answer
758 views

Can we combine extension tubes and diopters for greater macro magnification?

I want to increase the magnification of my Canon 100mm L Macro. I already have a set of kenko extension tubes. Could I buy a dipter to even increase further the magnification? For example Raynox ...
10
votes
1answer
320 views

What is the significance of the typical extension tube lengths?

I've been recently looking into getting an extension tube set for some macro photograpy. I've noticed that a lot of these 3 tube sets (for Canon EOS) have the same, very specific lengths: 13mm, 21mm, ...
8
votes
3answers
1k views

How Much Can Lens Magnification Be Improved Without Significantly Lowering Image Quality?

Currently I own only a 1X magnification macro lens (35mm F/2.8) but I am playing with a rented Canon MP-E 65mm lens which can go to 5X. The photography at that magnification is a world apart! The ...
3
votes
1answer
735 views

Does maximum aperture change with focus distance with the Canon 60mm f/2.8 macro lens?

This site says The Canon EF-S 60mm f/2.8 Macro USM Lens loses 1/2 stop at 1:5, 1 stop at 1:3, 1.5 stops at 1:1.5 and 2 stops at 1:1 (lifesize). Can anyone confirm that at 1:5 magnification, ...
6
votes
2answers
3k views

How can I calculate magnification ratio I get by reversing a lens?

I am looking for a way to mathematically determine the maximum magnification ratio that is possible/practical to achieve by reverse mounting a non-macro lens, prior to purchasing the lens. See ...
5
votes
2answers
588 views

How To Measure Viewfinder Magnification?

What is the easiest way to measure the magnification of a viewfinder? Must be able to do it for both electronic (EVF) and optical viewfinders. Also, I only have access to one focal-length.
5
votes
2answers
1k views

How can I estimate the reproduction ratio of an unknown macro setup?

If I have a macro setup consisting of more than a normal 1:1 lens (tubes, reversal, or anything else), how can I measure the reproduction ratio (2:1, 1:1, 1:2, 3:1, etc.)? What process can I follow ...
4
votes
1answer
574 views

Do you suggest using an extender/tele converter with a Macro lens such as Canon 100mm f2.8 macro lens?

Do you suggest using a teleconverter with a dedicated macro lens? I have tried out using a Kenko TC with canon macro lens - however I am not 100% satisfied with the "extra" magnification that I got on ...
24
votes
4answers
4k views

Does my crop sensor camera actually turn my lenses into a longer focal length?

So, I mount a 200mm lens on my Canon 450D. It effectively becomes a 320mm lens. Is this the equivalent of 320mm on a full frame camera? That is, from what I've figured out I get an equivalent field of ...
24
votes
3answers
11k views

How can I calculate what the effect of an extension tube will be?

There must be a mathematical description of the difference that an extension tube makes to a lens -- is it something that can be easily described? (For example, with teleconverters you can say things ...