I have been using a Tamron 90mm macro on a Canon 7D. I am considering the purchase of the Canon MP-E 65mm lens to start doing higher magnification macros.
Here is a summary of my research into MP-E65 lens based on a Canon cropped factor (CF) camera such as the 7D (took a while to line up the columns in the following table):
Lens magnification= 1:1 | Lens aperture=f/8.0 | Effective magnification=1.6x | DOF(mm)=1.120
Lens magnification= 2:1 | Lens aperture=f/5.6 | Effective magnification=3.2x | DOF(mm)=0.297
Lens magnification= 3:1 | Lens aperture=f/4.0 | Effective magnification=4.8x | DOF(mm)=0.124
Lens magnification= 4:1 | Lens aperture=f/3.2 | Effective magnification=6.4x | DOF(mm)=Not provided
Lens magnification= 5:1 | Lens aperture=f/2.8 | Effective magnification=8.0x | DOF(mm)=0.048
Lens magnification=10:1 | Lens aperture=f/2.8 | Effective magnification=16x | DOF(mm)=?
Notes:
1. The "Lens aperture" column is the required camera aperture selection to maintain an effective aperture of around f/16 . Seems the limiting effective aperture (due to diffraction effect) for a CF camera is around f/16 (and around f/22 for a FF camera).
2. The "Effective magnification" column is the actual magnification, taking into account a crop factor of 1.6 for Canon cropped factor cameras. Not sure if this is correct?
3. The DOF data taken from the MP-E 65 manual. It is probably based on a FF camera. Not sure if the DOF for a CF camera is similar for the same lens magnification or would it be different due to the effective magnification being different?
4. The 10:1 "Lens magnification" is from using the MP-E65 (at the 5:1 setting) in combination with the Lifesize Converter EF. The lens aperture is set to f/2.8 because that is the limit of the lens. The effective aperture would be f/30.8, which for a CF camera is an (significant?) issue due to diffraction.
Does my summary make sense or have I missed something?
Bottom line: is the MP-E65 a good paring with a CF camera? What are the pros and cons (compaired to using a FF camera)?
MP-E65 Lens on a CS Camera (7D)
Moderators: rjlittlefield, ChrisR, Chris S., Pau
That looks all about right, except that
- it doesn't go to 10x (
)
and "we" measure magnification onto the sensor, so 1:1 is 1:1 whatever sensor you're using.
The number rapidly loses its meaning of course, depending what you're doing with the image.
Depth of field depends on magnification and effective aperture. C of C depends on sensor pixel size, rather than sensor size, and diffraction depends on effective aperture - it can kill the geometrically calculated C of C. (I think I've written all that right, it's very easy to get it slightly wrong, and it depends "how you look at it".)
So yes, the "limiting effective aperture" figures you quote would be about right, depending how critical you need to be, and pixel size.
I tend to work things out from the final image I need. If I want a money spider's face at 5x for an image 1200 wide, my C of C can be a few pixels diameter so I can get away with f/5.6 or f/8 and use fewer exposures than at f/2.8. Recently I saw a professional photographer with extension tubes on the MPE, on APS. Horses and courses I guess.
F/2.8 at 5x isn't as good as a microscope objective if you want the finest though. But filling a FF sensor at 5x is harder, with those; it's objective-dependent.
On a FF sensor you'd need about 7x for the same field of view of course - so it's a transitional area.
I've been ogling a Canon 6D because 36mm is a more useful maximum field of view, outside, than 22mm, but I don't have a 100mm macro lens for a Canon. I have Micro Nikkors..
- it doesn't go to 10x (
)and "we" measure magnification onto the sensor, so 1:1 is 1:1 whatever sensor you're using.
The number rapidly loses its meaning of course, depending what you're doing with the image.
Depth of field depends on magnification and effective aperture. C of C depends on sensor pixel size, rather than sensor size, and diffraction depends on effective aperture - it can kill the geometrically calculated C of C. (I think I've written all that right, it's very easy to get it slightly wrong, and it depends "how you look at it".)
So yes, the "limiting effective aperture" figures you quote would be about right, depending how critical you need to be, and pixel size.
I tend to work things out from the final image I need. If I want a money spider's face at 5x for an image 1200 wide, my C of C can be a few pixels diameter so I can get away with f/5.6 or f/8 and use fewer exposures than at f/2.8. Recently I saw a professional photographer with extension tubes on the MPE, on APS. Horses and courses I guess.
F/2.8 at 5x isn't as good as a microscope objective if you want the finest though. But filling a FF sensor at 5x is harder, with those; it's objective-dependent.
On a FF sensor you'd need about 7x for the same field of view of course - so it's a transitional area.
I've been ogling a Canon 6D because 36mm is a more useful maximum field of view, outside, than 22mm, but I don't have a 100mm macro lens for a Canon. I have Micro Nikkors..