Canon 180mm Macro on 20D?

I'm with Herb in my lens usage - I probably like the 150mm so much because I shoot a full frame camera. Just like Alex likes the 105mm for his 1.5DX sensor, I like the 150mm for FF. I just wish I didn't have to use such a "bazooka" lens to get there! :-)

I don't use the 150 as a telemacro lens, probably because I've only made one dive using it WITHOUT the 500D diopter. The diopter is a +2 strength 2 element diopter and brings the close focus in to about 5" from the port tip - just perfect! The far focus range is still well within the lighting limits of my strobes, so I don't worry about focusing at infinity.

Cheers

James

Sorry for coming late to the dance on this one.

Thanks for the compliments also, it is appreciated. Someone else from the Nikon realm, Rand, has also had great results with a 2xtc and the 105mm.

I have shot the 100mm with the 1.4xtc and the 2.oxtc. Based on my use I find I prefer the 2xtc to the 1.4 because I am trying to achieve for lack of a better word, supermacro. I just didn't feel the 1.4 gave me a large enough change from the 100mm to warrant it's use for supermacro. I love the results but, you have to be very dedicated to very small subjects or parts of subjects. Something I think is actually better than just looking for plain macro subjects. (If that makes sense) More of a focused approach to image making. I also feel it is easier for me to try and take "moody" images with this set-up.

I use a wet diopter as needed too.

The set-up does get big and heavy doing this. Makes shooting the 50mm seem quite simple after a day of this set-up.

If memory serves me correct this is very close to full frame 100mm with 2xtc.

I'm using a full-frame camera, so you have to take that into account, but I probably use the Sigma 50mm 20% of the time (on night dives and/or when I MIGHT see a macro subject, but also want a fish lens), the 100mm 50% and the Sigma 150mm with 500D diopter 30%.

However, I expect that to change. I just got the Sigma 70mm macro lens, so I'll use that as a fish/macro lens (instead of the 50mm), and now that I've discovered I can use the 100mm with the Kenko 2X TC, I expect to be using that A LOT for macro (probably 60-80% of the time). That means the 150mm is going to get used less and less. However, my "wild" combo will be the 150mm with 2XTC (I've ordered a special manual focus ring from Seacam), and I'll be interested to see how that works (I'm not overly optimistic, BTW, for the reasons Alex has stated - I expect the 150mm to be a REAL pain to use with the TC!).

I also keep a wet diopter handy, regardless of what macro lens I'm using...just in case. I like that better than a screw on diopter (e.g., the 500D) because I can add/remove it DURING the dive as needed.

Thanks all!

It seems that many find the 50cm water column limit imposed by the 500D diopter is just right. Sounds like the 500D will be a great learning tool to force me to get close. I thought getting to within a meter was quite an accomplishment for some fish and I never got anywhere near a meter from a garden eel or midnight sergeant. Just more reason to include unlimited shore diving in my next trip so I can take all the time I need to practise without having to follow a DM.

Bart

PS closest focus distance is indeed measured from the film plane. For instance, for the 100mm Macro the spec sheet says:

"Closest Focusing Distance 0.31m / 1 ft. (film plane to subject)"

The working distance is the distance between lens and subject. Here the Canon page for the 100mm Macro says: "Inner focusing affords a long working distance of 5.9in. (149mm) at 1x." Although I think that "in spite of inner focussing" would be more appropriate. Inner focussing is the reason that the 100mm lens becomes only ~75mm at 1x focus, it accomplishes part of its focusing by reducing the focal length instead of extending the lens barrel. Without inner focusing, a 100mm lens at 1x should have a 200mm working distance.