Canon * button for focusing

Canon DSLRs give you the option of programming the * to become the AF button, thereby separating the AF from the shutter release.

How many of you have made that switch--or have consciously decided NOT to--and why/why not?

I have not used it yet but only have one trip under my belt with the 20D.

To simplify the changeover from the Rebel I chose not to use it on the first trip. I can see advantages and will be putting it to use on the next trip. I need to play with it a bit on land first.

I use it for high speed subjects using high speed shooting with AI Servo mode. This way once I think the focus is good, I let go of the * button while shooting at 8fps. Usually that means focus is locked and just metering is on. Of course if AI servo were out of focus when I release it, then I get a series of OoF shots.

I can also refocus again in the middle of a sequence if I deem necessary. Great for scenes where light is changing and thus metering should be constant, but the subject doesn't move much too.

This is all topside of course... u/w I haven't messed with it.

I use it for macro shooting underwater. Above water, I don't use it.

Cheers

James

I use it for macro. As I am inching closer to the subject I keep hitting the * button and locking the focus, when I think I have the optimum shot I pull the shutter lever. I can do the same thing by half depressing the shutter lever but this seems easier for me. As I get more used to the camera, I may quit using it.

Tom C

As an ex-Nikon user I still rely on the halfway shutter release bto activate focus! I ought to try otherwise and one day probably will........

I use * almost exclusively above water. Just starting underwater photography so not sure which way to go yet. I like to have more control over my depth of field.

I use * underwater. I like being able to lock in the focus, especially when shooting macro or with a shallow depth of field. Once you get used to it you'll find that you have greater control over the focus of your photos with it, especially with wide aperture lenses.

I like to use manual focus for macro, but also like to be able to shoot one-handed. So on my Nikon cameras (F100, D100, D2X), I use the AF-ON button for focus in the same way that the * button can be used. I get the focus point set using the button, and then fine tune the composition and exact focus point without refocusing. I only use it this way underwater; topside, I autofocus with the shutter release, unless I'm doing super macro topside.

This is an interesting discussion. I never use the AF-on on my Nikons, as I am very used to pressing the shutter half way to focus. One very effective technique (at least for me) was to hit the Focus Lock (AF-L) button when I have focus. This will trigger the shutter if you have the shutter pressed but the focus is not locking due to low light and/or subject contrast.

I use it on land, but not underwater. I find the half press trigger release move response as the housing (Ikekite) lever is kept in the off position with a spring. The level that hits the * button is not sprung, and as such it does not seem to provide the same responsiveness as the half press method. This could all just be my perception, but I find it harder to focus with the * underwater.

Damien

Hi Bruce,

I use the * button for macro all the time but it is reallly most useful with the Canon 100mm, though. Because the lens is "full time manual focus", moving autofocus to the * button allows you to have both options available underwater without having them try to fight each other. In other words, you can leave the lens MF/AF switch in AF. When you want to focus manually, you can do it without havng the half-press trying to override your focus selection. When you want to use AF, you just use the * button.

Mike

Never.......Tried it underwater a few times, even on my Nikon D100 and still am happy with the spring retracted trigger on my Ikelite Rebel XT housing.

Not sure how much faster people think they can pull the trigger using this frequently touted method.

YMMV

David Haas

I set my 20D to use the * button for focus control the day I bought it and have never, for any circumstance, switched back to shutter button control. It took a while for me to shake the instinct to use the shutter button for focus. Shifting focus control between two buttons would be for me like switching between an RPN and a non-RPN calculator - just added confusion. I can't think of a situation, above or below water, where I would not prefer to use the * button.

-Brad

With my rebel * focus was not an option. But since I have had my 5D i've been loving *focus above water. I'll have to wait how it feals under water.

My first trip with my 20D and Subal housing was to Port Hardy, BC. I used the '*' button extensively for my 60 mm macro shots. I found it very useful for several reasons:

- thick 5 mm gloves made the half press method less reliable

- semi-frozen hands also made the half press difficult to control

- I could use the '*' AF to focus on a particular spot on the subject using the centre AF point, then re-frame for the desired composition and rock in/out for sharp focus before pressing the shutter

- if AF was uncooperative on the particular subject (even with my Mod Light), then I could point the camera at something completely different (but with good contrast) that was the same distance away and focus using the '*', then re-frame, rock, and shoot

Note that I don not have the manual focus port or ring for my 60 mm lens, so MF was not an option.

There were several instances where I did not want to use the '*'. I found it quite simple to go into the menu and switch from option 3 to option 0 and return the shutter to "normal" operation. The best of both worlds.

With proper timing, I was also able to trigger the '*' button immediately followed by the shutter, therefore achieving similar operation to the "normal" shutter operation.

I deviate from the norm, and choose * to be 'Focus Lock'. It's there when I need it.

My pictures still seem to turn out alright

~Matt Segal

I aways use it for UW macro 100mm and 60mm (both USM) because these lenses can be used with manual and auto focus at the same time, It's so good !

Regards, Fabio

I aways use it for UW macro 100mm and 60mm (both USM) because these lenses can be used with manual and auto focus at the same time...

<{POST_SNAPBACK}>

Does anyone know if the Sigma 150mm macro lens can also be used that way--with both manual and AF--or is it just the Canon ultrasonic lenses that let you do that? WIll it damage the Sigma lens to put it in AF mode and then use the * for AF sometimes, but manually focus it (to fine tune, etc.) as well?

Yes, sigma's HSM is identical to canon's USM. So that works the sigma 150mm macro as well as all of sigmas lenses with HSM.