100mm or 600mm macro??

[Titanite]

Hello,
Im trying to decide between a canon 100mm 2.8L IS USM or a 60mm. For people with the 100mm, what is the largest critter you can photograph? I have never shot a 60 or 100mm lens. I like to shoot small stuff (nudi's, small craps, cleaner shrimp etc), but with a 100, what is the biggest critters I would be shooting?
Thank you in advance,
T

 

[smellzlikefish]

How are the pics of small craps coming out? I've never thought to shoot fecal matter, but find the idea entertaining. I see a picture book in the making...

 

[Titanite]

Ahh CRAP! I meant crabs!

Should give a few people a laugh anyways!!

 

[under water]

With the 100mm lens you get 1:1 magnification at about 6 inches from the end of the lens. For the 60mm, you get 1:1 at about 3 1/2 inches from the end of the lens. Add a housing and port and you might be getting really close with the 60mm. Seems to me, the 100 has the edge there. So I think the difference in MWD (minimum working distance) should be factored in.
Now, If you could find a 600mm macro lens.. Wow.. that would be a microscope!

 

[bvanant]

What underwater was saying is that you can shoot the same size things with both lenses. You can shoot whale sharks with either lens if you have clear water and can be far enough away. On the other hand, you would need really big strobes. Don't think about what the largest thing you can shoot is but think how far away do I need to be to fill the frame with that subject.
Bill

 

[Ozwald]

Crop or full sensor?

 

[Titanite]

its a crop, 1.6 canon.

 

[doctormike]

I have both of these lenses - 100 mm Canon macro and 60 mm Tamron macro. Used the 100 mm a few times and gave up. The 60 mm is MUCH better, much easier to use. Unless I was sitting glued to the bottom, braced well, and shooting something VERY small, I found the 100mm lacking. I never use it anymore, and didn't bother getting a port for it when I upgraded my housing.

You use a telephoto in topside nature photography to get yourself close to something skittish, but the same situation really doesn't arise underwater. Yes, you can get the same framing from a bit further away with a 100 mm lens, but you will still be very close to your target with either lens, so you will need to rely on your buoyancy and observation skills to get the shot. The 100 will be useless for picking off something big at any distance - remember that the number one rule of underwater photography is to keep the water column between camera and subject to a minimum.

Neither lens is for anything further than a foot or two from your camera, unless you are cave diving in gin-clear water. Use your wide angle for the whale shark.

 

[Titanite]

Any other comments on the 100mm??

 

[dynamo]

I have the 100mm IS Macro and have found the limited dives I've done on this lens hard work, lining up the intended target in the viewfinder is fairly diificuilt on a mixed background but do find the results make it worth the hassle.
.. But it is useless for free-swimmng fish shots resulting (for me) in off centre head shots. For fish sots my next purchase will be definitely be the 60mm macro. Have included a few shots to illustrate what I mean.