[berkshire bee]

I use a 50mm Pentax macro lens with 2x converter. I'm happy with the pictures it takes. My question is, all other things being equal, would a straight 100mm macro lens do a better job?

[Bramela]

Yes, I would say so, on at least one point, a converter puts more glass between the sensor and the subject, so there must be some degradation in the quality of result.
Whilst Tc"s certainly have their place, I don't personally feel that they are recommendable for macro photography.

[Raybo]

Yes, I would say so, on at least one point, a converter puts more glass between the sensor and the subject, so there must be some degradation in the quality of result.
Whilst Tc"s certainly have their place, I don't personally feel that they are recommendable for macro photography.

I agree with Bruce.

I went from extension tubes to a 50mm 1:1 macro and it was bliss, than I recieved a Vivitar Series1 105mm..........................

I couldn't even imagin' a Voight 125 or Pentax 200! (only in my dreams)

[berkshire bee]

okay, you've got me drooling now

[RioRico]

Now it's time for me to repeat my spiel about how enlarger lenses (EL's) on tubes and bellows are the way to go. That is, unless you use flash with macro shooting, in which case you're better off with a macro prime with aperture automation (A-type or newer). If you're not a flash-head, read on.

EL's are cheap & abundant & small & lightweight, have edge-to-edge flatfield sharpness, and those longer than 80mm can reach infinity focus on most bellows and thus can be used for general non-macro shots too. Common 75-80mm's that don't reach infinity are still great for headshot portraiture. EL's longer than 135mm may need tubes added for macro work. And most EL's are not coated -- they're not designed to be aimed INTO lights -- so use hoods.

Bellows are cheap, often ~US$30-40. Tubes are cheap. For less than the cost of one battered used M42 macro prime, you can have a set of extraordinary glass in a variety of focal lengths. Much of the cost of any camera lens is the body, mainly the focusing mechanism. With EL's you skip that, and only buy the glass and aperture iris. Some premium-name EL's fetch premium prices, but even highly-regarded EL-Nikkors can (with luck!) be had for under US$20. Most of my EL's were under US$10 -- batch-lots of 50-75-90mm's are sometimes four for a dime.

Most European EL's are M39/Leica screwmounts; M39-M42 adapter rings are VERY cheap. Some Japanese EL's are M42, the rest are M39. Many USA EL's have odd-size non-metric mounts. I use cheap plastic camera body caps with holes cut in them as mount adapters. And you can use cheap safe flanged non-infinity-focus M42-PK adapters for the final mounting.

And bellows can open the path to optical exploration. For 'period' effects, use projector glass, or lenses scavenged from old medium-format and polaroid cameras. For 'interesting' (ie lousy) effects, use eyeglass lenses, magnifiers, fresnel sheets, other uncorrected optical materials. Great cheap fun! Don't leave home without them!

[bdery]

I use a 50mm Pentax macro lens with 2x converter

Why the 2X converter?

[rhodopsin]

50/4 with 2x TC <=> 100/8

S-M-C 100/4 is two stops faster.

Are you using TC with 50 for more magnification, or for more working distance? Extension tube gains magnification, has less light reduction than TC, but limits focus range to closeups, at less working distance, while TC+50 and 100/4 both will focus to infinity.

[berkshire bee]

I've been using the converter for more magnification