nureality wrote in post #8259066
A 1.4x TC + Tubes won't give you more magnification, just more working distance.
No, not true. A TC magnifies the FL, while maintaining the exact same WD as the lens without TC. Hence magnifcation will be larger at MFD, and by exactly the magnification factor of the TC. WD will only be greater at exactly the same magnification.
Thats the problem that the OP experienced when trying to use the 135L. Its MFD kept him further away from the subject, and the tubes only serve to allow you to focus closer than native MFD, but the native MFD is the lynchpin anyways.
Again, no. It is a combination of MFD and FL, not just MFD, when using extensions, whether they are extension tubes or bellows.
In general, Macro photographers fall into 2 groups... (1) the people who want to get as close as possible to their subjects (these people buy the 60 Macros, 100 Macros), and (2) the people who feel they need some working distance (these people buy the 150 Macros and 180 Macros).
That's a rather simplistic view of the world IMO, with which I happen to disagree. There are a few more groups, IMO.
Adding a TC to a lens even when it has a tube attached, extends its focal length.
And its maximum magnification. To get maximum magnification, extender or converter is fitted to camera, tube(s) or bellows between converter and lens. This because you also double your extension this way (lens formula).
I've done a bunch of macro stuff around the house with my 50/1.4 + 3 sets of tubes... and have experimented with my 2x TC in the mix. The 2x TC just forces me to move the rig back from the subject.
Only for the same magnification.
I've taken some shots with my 50/1.4 + 3 sets of tubes (1 dumb set, 1 Kenko DG set, 1 macro bellows = all 3 = roughly 280mm of extension), the results are close to 10-12:1 magnification... very wild stuff.
The MFD of the 50 F/1.4 is 45 cm, with a magnification of 0.15X, which means image distance is approximately 63 mm. Add 280 mm to that, which results in a new image distance (back nodal plane to sensor) of 343 mm. Using the lens formula, that equates to a object distance of 58.5 mm, and hence a magnifcation of approximately 5.86 X. Spectular still, but slightly less than indicated.
For anything living tho, tubes can go so far, because they rob you of stops of light - something to the order of about 1-stop per 12mm of extension. The 3 sets together rob me of literally over 10 stops of light.
5.86 X magnification results in about 5.5 stops of light. Do note that light loss depends entirely on magnification, and hence both on FL and total extension) used. For every sqrt(2) of extra magnification factor, or approximately 1.4X additional magnification, you lose a stop of light extra.
The only way to shoot with such a rig is with LOTS of light sources (I used 5 LED flashlights to light a single bottle cap) and hence must be still-life subjects and you need a tripod. For my shots of snail fornication dubbed "Snails Gone Wild!" on my Flickr, I used my 100mm f/2.8 Macro + 1 set of tubes (Kenko) to maintain some semblence of speed and ability to handhold + used my RayFlash as a macro light to make it possible to shoot (those shots were taken outside after dusk with little streetlight to speak of).
That's impressive nonetheless, those shots that is.
Kind regards, Wim
