Unconfuse me please

[dicklaxt]

I took this with a Tamron 90 @ 1:1,I then resized it to 600 x 450 for this post,no crop. The physical size in photo is right at 3 times larger than the actual size of the scale,,,,,,,,explain what magnification I am dealing with 1:1 or 3:1,,,,,,,,,, and why.

This is Av @ f29 and 1/8"

dick

[dicklaxt]

This is the same setup with a 25mm ET added,now what are we talking about here in regards to magnification?

[LordV]

First shot is around 1:3 assuming a 1.6 crop camera- The lens can't be at minimum focus.
2nd shot is around 1:2.
Magnification = sensor width/mm across picture
For a 1.6 crop camera sensor width = 22.5mm

Brian v.

[John_B]

dicklaxt,
Your Exif says you are using a 40D which has a 22mm wide sensor. If your macro lens was set at 1:1 (which I don't believe it was) you should only get about 22mm of the ruler in the photo (0.87" which is less than an inch).
Also an aperture of f/29 is so not needed for a flat subject ;)

[dicklaxt]

Well chit ,I'm such a dummy,I don't doubt you are correct but I don't have a clue as to what you saidbw!,I guess this little sign is saying I need to go read some more and just when I thought I was getting smart.:oops::oops::oops::oops::oops::oops:

dick

[John_B]

dicklaxt,
Try setting the lens on MF (manual focus) and put it on its closest focus, then set your aperture at f/8 and take the photo again and you should see the difference ;)

[Warl0rd]

to be at 1:1 you have to use the lens at its minimum focusing distance. its easier to set it MF, focus all the way to the minimum then move the whole rig back and forward until the ruler is in focus.