[brecklundin]

Same here. I was really into number and group theory, as I recall. I was gonna be the guy to prove Fermat's last theorem (yeah, right). Seems like a distant past life - I barely remember any of it now. It is indeed, as you suggest elsewhere, more about the process of logical thought that I feel I continue to put my math background to good use.

I too really loved abstract algebra and number & group theory as well...now as to Fermat's Theorem...HA!! Me? I always wanted to come up with a definition for a Mobius SPHERE, how is that for out there? ....and it seems like a foreign language to me anymore. I recently dug out my 120pg text from my gradual student course on Abstract Algebra and what was one reference material is basically gibberish to me. I can still manage difference equations, Bessel Functions, Gamma Functions and lots of Diff EQ stuff. Solving systems was pure joy for me. My primary focus was in, well to use a more common name but Chaos Theory/Nonlinear systems. but nothing applied only theory and systems. I really miss it and had once upon a time planned on finishing the Piled-Higher-n-Deeper but started a network design and consulting company (Did Netware when it meant something to have an ECNE/CNI) and then life took over...still like you say, no education is ever wasted and the approach to solving probs is the same no matter what line of work you find yourself in...

That confused me when I say the numbers on Dimitrov's site showing the 100mm macro having a minimum focus distance greater than I was getting with my M135/3.5 + Raynox 150. I'm now assuming that this is the reason. I could work through the numbers, but I'm content to just assume in this case :-)

I bet that is exactly what got ya on the MFD...it depends, no not the wearing kind but the conditional kind of depends, on the point of reference. Like I mentioned I was really disappointed when I found out my DA 35ltd's MFD was not from the front element but the focal plane which makes 1:1 about 1" or so....4"-5" I was fine with but 1" is causing me a lot of frustration on my product shooting when I need to get nice tight shots of jewelry. Otherwise I love the 35ltd as a product photography lens. Still I find I am likely to pickup another 180mm Sigma (I had the Canon mount version I bought used and LOVED it even with the weight...nice studio or controlled setting lens)...I was also bummed to learn Sigma does NOT offer their AWESOME 150mm Macro in a Pentax mount. I just need the working distance and I actually need a true 1:1 so I can stay out of my own way...

??? Have you followed the Raynox thread? Used with a good lens to begin with, you'd really be hard pressed to see a drop in IQ compared to the other methods you might be considering. On the other hand, if you're OK with reversing rings and so forth, it's not like there's any real advantage in the Raynoxes, either. Revering rings do gie you a lot more flexibility if you've got a variety of lenses you could use them with.

Honestly I never gave the Raynox thread a first glance...I will look into it though...playing with reversing and what not are purely recreational/wtf sorta things for me. So eventually I might just grab a Raynox as they are not too spendy, yet anyway. I have this twisted idea of reversing my 77ltd in my 35ltd...see what I mean, I genuinely need therapy!! hahahaha...

I was thinking that if I ever have some time I might write a page to act as a calculator for most of the equations...I already scarfed the DOF Calculator for my Clie PDA but I really dunno what use running these numbers might have for real world use.

Plus I am still trying to figure out where the focal plane mark is on my K20D...which after today's walk with my 77ltd, might be on the chopping block...65 shots and maybe 1-3 really fugly keepers. I was playing with "P" mode set to MTF and nothing really worked worth a dang!! There is always tomorrow....and back to my friend "M" mode...