Comments on: How to calculate subject size from a macro photo

By: Dave Kennard

Dave Kennard — Sat, 17 Sep 2016 16:00:30 +0000

In reply to David.

Hi David

The ruler tool measures the length of the line you draw with it, it doesn’t measure only along the horizontal axis (unless you draw a horizontal line with it).

So you can use the line length given by the ruler tool, no need for trigonometry!

By: David

David — Thu, 18 Aug 2016 14:39:23 +0000

I appreciate that this is an old blog. However I have a question about this.
The Canon 450D sensor size is 22.2 x 14.8 mm
I.e it is not a square, therefore as your bug is not parallel to the bottom line should not the calculations take this into account?
Or am I missing something?
I have not used trigonmetry for many years

By: Dave Kennard

Dave Kennard — Mon, 02 Mar 2015 10:37:42 +0000

In reply to Ian Wilkinson.

Hi Ian

I think the MacroMagnification is a Canon specific metadata property, so it would only be recorded by Canon cameras. For other cameras you’d need to try and remember to write down the magnification for each shot, or take a photo of a ruler each time you change the magnification.

Regards

Dave

By: Ian Wilkinson

Ian Wilkinson — Sun, 01 Mar 2015 19:12:48 +0000

Hello David, thanks for providing this helpful information.

Would you expect the MacroMagnification data to be recorded in RAW files created with a Sony A7R, which is connected to the Canon MP-E 65 via the Metabones EF to E IV adapter?

I suspect that some of the metadata is omitted, because although ExiftoolGUI reveals LensType : Canon MP-E 65mm f/2.8 1-5x Macro Photo + Metabones Adapter and lots of other stuff, the magnification figure isn’t revealed.

Thanks for your help.

Kind regards,
Ian