Originally posted by Marc Sabatella "Good" working is a relative term. If you want more than 1:1, you're dealing with inches. How many inches depends on focal length - 1:1 at 200mm is achieved at a much longer working distance than 1:1 at 50mm. So the longer the focal length the better as far as that goes. But you're still going to need skill and patience, as we're talking a matter of maybe 6-8 inches for 1:1 at 200mm, versus maybe 1-2 inches for 1:1 at 50mm.
That's a nice thing about the use of a closeup lens like the Raynox (and reversing stacks are similar in principle, I guess - just a lot more awkward to deal with). Unlike extension tubes, they provide more magnification with longer focal lengths. So if you've already got a 200mm lens, any attachment that makes it 1:1 means you'll have a "decent" working distance by macro standards. Whereas trying to achieve the same magnification starting with a 50mm lens means much smaller working distances.
The DA*300 has a much closer minimum focus distance than some of the older Pentax 300mm lenses. I like this lens a lot and it with just a little cropping it can give pretty good results, but it's not really "macro". What do you think of a Raynox 250 on this lens?
Meanwhile, a lot of my lenses (including the wonderful D-FA 100 WR Macro) have no aperture ring and of course Kenko no longer makes their auto extension tubes
in Pentax mount. (Why???
) BUT, I think I've found an uber-cheap solution, just ordered a 49mm-49mm reversing ring for about $5. I'll be trying the F50/1.7 and FA35/2, reversed on the D-FA 100. Can't wait to try that!
So what is the opinion about the 300 + Raynox? I'm just thinking it would offer very good working distance...