100mm lense problem with 20D?

[kriptap]

I have the 20D and one of my lenses is the Canon 100MM, I use it only underwater in my housing, I like what the lense can do but it's really poor in low light, or at least I find it very poor. I bought it new and saw it was poor in low light right from the start.

So my question is, is there another 100MM lense that will work with the 20D? I'm hoping another make or model but still round the 100MM range will be better.

Thanks

You can take a look at some of my photos here, you'll see the 100MM in action:
http://www.digitaldiver.biz

[PaulB]

Sorry, which 100mm Canon lens would that be? The 100 f2.8 Macro or the 100 f2?
I don't know of any other 100mm focal length Canon lenses and those two aren't exactly bad at focus speed - although the earlier 100 f2.8 Macro hasn't got USM and is not as fast as the later USM version.

[ddelallata]

I have a post in the EF and EF-S lens section about the slow focusing speed in low light conditions with the 100 mm Macro. Have a look when you get a chance.

[kriptap]

It's the 2.8 USM, it's new straight from the shop. I also have the 17-85 and it is great in low light, really great, it will focus in almost pitch darkness, but the 100 is very poor. As there is no other lense like this looks like I just have to grin and bare it.

Would the 28-105MM be a good choose?

[ddelallata]

It's the 2.8 USM, it's new straight from the shop. I also have the 17-85 and it is great in low light, really great, it will focus in almost pitch darkness, but the 100 is very poor. As there is no other lense like this looks like I just have to grin and bare it.

Would the 28-105MM be a good choose?

the 28-105mm 3.5-4.5 USM II has very fast focusing speed but it's optical quality is nowhere near as good as the 100mm f 2.8. If you scroll down on this
link (http://photonotes.org/reviews/ef-lenses/) you'll find a good review on the 28-105..

[wolf]

There is the Sigma 105 mm f/2.8 Macro EX which is comparable to the Canon 100mm in image quality.

[J Rabin]

but it's really poor in low light
Beautiful photos BTW. As Ddelallata noted below, we just answered this for him in his thread. Check it. It gets asked like once a day.
It's not a lens problem, it's a magnification problem. Macro lens makers ought to put it in their manuals.
When you are macro close focusing near life size (15cm from subject with the Canon 100mm f/2.8 macro) you effectively lose about 2 full f/stops of light.
So, at near life size focus, think of your f/2.8 lens as an "effectively f/5.6 100mm in terms of aperture focusing efficiency. Only 1/4 of the light!
All macro lenses from all manufacturers work this way. I think it is caused by the fact that as you macro focus (magnify), the lens elements are moving further from the sensor. If you need easier focus, back up a few cm and shoot at, say 1/2 life size. Then you only lose half your effective light instead of 3/4 (haha).
If you need the magnification, then you need a macro with longer working distance, like the Sigma 150 or Canon 180. See my posts on these.
J.

Edit. an advantage you have is the 20D was designed with a coarse ground glass focus screen, just for manual focus in this kind of situation. When focus goes in and out, it really pops. I think Canon did much right with the 20D for macro photography.

[tim]

Seems that the 100mm macro does focus slowly in low light, not much you do about that really.

[kriptap]

Thanks all (J Rabin) so my last question is:

The 100mm is a perfect lense for a type of image that I do a lot of shooting for i.e.
http://www.digitaldiver.biz/cgi-bin/pics/emalbum.cgi?c=show_image;p=Shy%20Hamlets;i=2;in=IM G_1362-1.jpg

I saw Sigma make a Telephoto 105MM f/2.8 EX DG Macro Autofocus, would that lense be able to do what the Canon 100MM can? and as it's a 2.8 that should help on the low light?

Thanks for sharing your knowledge

I should also say it has to fit in my housing..

[ddelallata]

I would just keep the Canon 100 Macro. It's optical quality is just amazing. Even if it takes a little longer to focus, I doubt that the Sigma can compete with what you already have.

[J Rabin]

Nah. The Canon 100mm is really best of class, along with Nikon and older Olympus gear for this work. The older Sigma design had the front lens element extending as you focused. Kiss of death for your work, compared to Canon's internal focus.
Most manufacturers macro lenses are f/2.8 or f/3.5. The loss of "effective" f/stop light is due to the lens elements moving to obtain the magnification in the lens. The camera's TTL meter automatically takes care of metering, but it doesn't get you more light.

The Canon 100mm macro is a stellar lens. Add light, don't change the lens. I think your solution is going to be a waterproof lighting setup, either continuous light, or flash.

Life could be worse. The Canon MP-65 lens says f/2.8, but has an effective f/stop of f/16 when racked out to 5x. In the old days, Nikon's old film SLRs showed the "effective" f/stop when connected to a macro lens. Canon's have never provided that feature. But, as above you need to bring supplemental light to your challenging task. J.

[kriptap]

Thanks for the advice, I have 2 large strobes so I'll just get a couple of focus lights, thanks again.