How can I measure what magnification I'm getting?

Wail

Wail

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Wail
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I've thought many times about posting this, but I can't for the life of me figure out how to calculate the magnification on this.

I know many macro lenses will state that I can get 1:1 magnification, while others are 2:1

However, things get a bit complicated for me when I start to use extension tubes (et) and reversing rings (rr)!

I have the following lenses: -

Sigma 20 f/1.8
Nikon 28 f/2.8 AI-S
Nikon 35 f/2
Nikon 50 f/1.8
Voigtlander 58 f/1.4
Sigma 105 f/2.8 macro
Nikon 70-300VR

I've used Kenko et on my lenses to great effects, but I couldn't for the life of me figure out how to calculate what magnification I am getting, or even what's the minimum working distance (I've used a tape measure to measure this .. not very scientific).

It gets worse when I start to reverse mount my lenses (I've done this with the 28 f/2.8, 35 f/2, and 50 f/1.8 .. since all these have a 52mm front thread).

Can someone please point me to where I can get some explanation. Or better yet, explain it to me.


Thanks



Keep in mind, please, I am still in UK and hence room temperature is just about 20C (room temperate ≈ my IQ).
 
Someone, sorry I can't remember who, recommended me to take a shot of a ruler across the frame. 1:1 will show as many mm on the ruler as the width of the sensor. So for the 450d which is 22mm across, it's 22mm. I used this to work out the magnification I get with the Raynox on my 55-250. HTH
 
I told you about IQ and room temperture :nono:

Could you please explain that ...

"1:1 will show as many mm on the ruler ...." :shrug:
 
1:1 is true macro or life size , as has been said take a photo of a ruler and if your sensor is 23mm wide you hill see 23mm in the image

1:1 -
1-1.jpg

​

If you shooting at 1:2 (1/2 life size) you will see approx 46mm

1:2
1-2.jpg


and at 2:1 (twice life size) you would ses approx 11.5mm
 
Great! I got it (I think, hope and pray) .. thank you very much.

I guess, this will work irrespective of what lens, tc, et, rr I use ... and hence should be able to get the magnifications I am achieving by just getting the ruler's reading off the shot I take :shrug:
 
Wail said:
Great! I got it (I think, hope and pray) .. thank you very much.

I guess, this will work irrespective of what lens, tc, et, rr I use ... and hence should be able to get the magnifications I am achieving by just getting the ruler's reading off the shot I take :shrug:
Click to expand...

you need to set your lens to its maximum magnification first by manually focusing the lens to its closest focusing point then point the lens at the ruler and focus by moving the camera backwards and forwards, when its in focus take the image, read of how many mm you can see in the image .
 
Wail said:
I told you about IQ and room temperture :nono:

Could you please explain that ...

"1:1 will show as many mm on the ruler ...." :shrug:
Click to expand...


Oops sorry... I didn't word that well, it's been a long week :D... I did try to see what Nikon you had, but it's not listed in your profile, google will be able to tell you the width of your sensor.
 
I have the D700 :)
 
A big thank you to all who've posted and helped :thumbs:

I guess I ought to run off and see what magnifications I get, then :)
 
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