My new close-up rig...

[twebster]

Strictly speaking, this new rig is for close-up images rather than macro images. I only got to test it out for about an hour, yesterday.

1. Canon EF 300mm f 4L IS lens
2. Jobu Jr. gimbal head
3. Velbon El Carmagne 630A tripod
4. Acratech leveling base
5. Canon EF 1.4x II teleconverter
6. Canon EF 25mm II extension tube
7. Canon EOS 20D dSLR
8. Double bubble level
9. Canon Off Shoe flash cord
10. Canon 550ex electronic flash

So far the images are excellent.

[rjlittlefield]

Impressive setup!

I'm curious about placement of the teleconverter and extension tube.

Usually I see this stuff set up as main lens, then extension tube, then teleconverter. In that configuration, the extension tube shortens the close focus distance by just the same amount as it would without the teleconverter, and the teleconverter makes the result X times bigger without changing the focus.

The way you have them here, I'm having trouble guessing what will happen.

I ran a quick experiment using very different lenses (Vivitar 135mm lens and 2X teleconverter), and I got closer focus and higher magnification by setting up as lens/tube/teleconverter --- 2" field width at 21" vs 3.5" at 40".

But I figure the behavior probably varies between lenses (perhaps by a lot!), and I have no idea what yours will do.

Have you tried it both ways? What's the difference, with your lenses?

--Rik

[twebster]

Hi ya' Rik,

The reason I have it set up this way is so that I can retain autofocus with the 20D camera. If I go lens + tube + teleconverter I lose autofocus.

Best regards,

[rjlittlefield]

Interesting! I didn't even think about autofocus somehow depending on the order. It shouldn't matter, in theory, but obviously that theory is missing some key elements.

Remember the good old days when all we had to worry about was the light and the mechanics? Then came the electronics, then the digital electronics, then the communication protocols... I can hardly wait to see what refuses to talk to what, next

--Rik

[twebster]

I like things as they are now, Rik. I would not care to go back to the "good ol' days".

Probably the key piece of equipment in this setup is the small Jobu gimbal head. If you have never used a gimbal head with a telephoto lens you're missing out on a versatile piece of equipment. I can smoothly follow flying dragonflies or any other active subject and still maintain stability. Try a small gimbal head with a telephoto lens and see if you don't agree with me.

[Mike B in OKlahoma]

Glad it is working for you Tom, the 300/4 IS is a great lens for what you're using it for.

I came too lately to this (2002) to remember the good ole days. I've never known this any other way than digital. Unless you count snapping tourist picks with Instamatic cameras!