student help chooosing new lens

[D.J. McNeil]

I'm only posting the image, so that it won't look empty.

Anyway, I'm a poor little college student, and I want to shoot macro photography. I have a Canon Rebel XTi, and 2 lenses (18-55mm and 100-400mm) I have a 1.4X tele-extender and a 2X extender. I have a decent flash, so I think I'm good there.... but I REEEAALLY want a new macro lens... or rather... a macro lens.
A friend of mine says that anything smaller than 100mm would not due, since it would scare the insects away to get so close (I think that I'm a pretty good bug-stalker, as I am an entomology student, but that's beside the the point).
My budget is $200-$300, but I might be able to stretch it a bit.

I really want to shoot insects, and my 18-55mm wide-angle does not suffice. it did a halfway decent job on this photo, and you may critique it if you like ( I would greatly apreciate it), but my main reason for posting is that I DON'T KNOW WHAT LENS TO GET!!!!!

Oh, and if the photo did not upload... ignore anything I wrote about it.... if it did upload... ignore this...

[D.J. McNeil]

Dang... it didn't upload

[D.J. McNeil]

AAAaaaaaaaannnnd no replies.... Dang... Well, I guess this IS bird photographers.... not Bug photographers

[Daniel Cadieux]

I have the 100-400 myself, and with its relatively short minimum focussing distance it makes a good "macro" lens with extention tubes slapped on. Those tubes are very inexpensive, especially for a student on a budget.

[Harold Davis]

i think the sigma 150mm 2.8 is around $600. awesome sharp lens and a great price too!!

[Taylor Yeager]

I agree with Harold, that is the lens to have. Why not sell your 2x and pick one up?

[Roger Clark]

I suggest selling your 100-400 and buying a 300 mm f/4 L IS. It is a sharper lens than the 100-400 and does well at macro too. Plus it is a great wildlife lens. Check out Greg Lasley's site and go to the dragon flies section:
http://www.greglasley.net/index.html
Many of the dragonfly images are taken with a 300 f/4. I met Greg at Bosque a couple of years ago and saw his album of 13x19-inch prints of dragon flies that were stunning, taken with the 300 f/4.

Roger

[Doug Brown]

The Canon 100mm f/2.8 macro lens is excellent and affordable.

[D.J. McNeil]

Yeah I was thinking about the 100mm f/2.8 because it was the best value, and I understand that it has one of the sharpest focuses of any canon lens... not to mention the fact that it is not digital specific.
As for putting extension tubes on the 100-400, wouldn't my depth of field be very limited if I tried that?

[D.J. McNeil]

Oh, and I could never sell my 100-400mm. I use it for all of my bird photography.

[D.J. McNeil]

I am intrigued by the sigma 150mm 2.8... but it seems a bit pricy... But, as I'm learning, Macro lenses are not easy to make, and therefore, are expensive by nature.

[Roger Clark]

Yeah I was thinking about the 100mm f/2.8 because it was the best value, and I understand that it has one of the sharpest focuses of any canon lens... not to mention the fact that it is not digital specific.
As for putting extension tubes on the 100-400, wouldn't my depth of field be very limited if I tried that?

Depth of field in macro photography is controlled by magnification, not extension tubes nor focal length.

I also have 100-400 L IS, but it is not a sharp as fixed focal length lenses like the 300 f/4. I get sharper images with my 300 f/4 or 300 f/4 + 1.4x TC than I do with my 100-400. And the 300 f/4 is a lot smaller and lighter.

For macro photography of bugs, you need some working distance or you will scare some subjects away. A 100 mm lens means you must get very close. A 180 mm macro would be much better, or the 300 f/4.

Roger