aperture control (1 Viewer)

I will start by apologising for what could be the first of many. probably oft posted questions. I am about to get my first DSLR so am at the bottom of the learning curve. I will be using the Canon EF 50mm f/1.8 in conjunction with extensioin tubes for mostly insect photography. As i will be using cheap tubes there will be no auto focus, but how do i control the aperture, if at all ?
Rob.

Hi Rob. Do you normally shoot in aperture priority?

If not change to this mode (AV) and the settings can be easily changes. For most macro work shooting above f8 gives you a good depth of field.

Cheers

Hi Marcus, thanks for the swift reply, i normally shoot in shutter priority but thats on a compact. So are you saying that all i will loose with the tubes is auto focus ?

I don't use tubes myself, but I can't see what else you would lose.

rob lee said:

So are you saying that all i will loose with the tubes is auto focus ?

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You will also lose a bit of light but not a lot (maybe 1/3 stop at a guess). Most extension tubes are AF type are you sure yours are manual only?

my tubes (kenko) retain AF and full metering

Duke Leto said:

my tubes (kenko) retain AF and full metering

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I am not sure that metering is an issue Steve as any Camera or Extension tubes will meter correctly regardless, as I see it. TTL metering will always be what the camera can see Through The Lens regardless of what is in between - that's how people get away with taping tc's, the camera would report an incorrect focal length and Aperture but still give correct metering.
What I meant by losing some light would not effect metering, it just means that you would get a slightly slower shutter speed than if you used the lens without tubes under identical conditions.

Have`nt bought them yet but they are only about a tenner (literally just tubes). So i`m pretty sure they wont AF.

rob lee said:

Have`nt bought them yet but they are only about a tenner (literally just tubes). So i`m pretty sure they wont AF.

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They probably wont for that Rob, still no great shakes as lots of people manually focus macro shots out of choice anyway. I would say just about all the top macro shooters use manual focus so you will be in good company .

The real bigy with macros is DOF, the closer your are the less you will get so you will have to stop down and that means slower shutter speeds and slower shutter speeds mean more chance of soft images due to camera shake. Its a big challenge and one I have never mastered.

The best of luck to you anyway Rob :t:

Roy C said:

The real bigy with macros is DOF

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Which is why i was asking about aperture control to begin with. I will be photographing mainly (hopefully) still subjects & using a mini tripod so slow shutter speeds will not be too much of a problem. A lot of top macro shots are taken with shutter speeds of over a second. I have only used a compact before so dont know what the effects of mirror slap? might be. Camera arrived about an hour ago & am now waiting for battery to charge before i can start playing. As i get more proficient i hope to have a look at image stacking, another way to counter the lack of DOF. By the way Roy you`ve got some nice macros yourself on your website. I particularly like the Bush Cricket. What lens did you use forr that ?

rob lee said:

Which is why i was asking about aperture control to begin with. I will be photographing mainly (hopefully) still subjects & using a mini tripod so slow shutter speeds will not be too much of a problem. A lot of top macro shots are taken with shutter speeds of over a second. I have only used a compact before so dont know what the effects of mirror slap? might be. Camera arrived about an hour ago & am now waiting for battery to charge before i can start playing. As i get more proficient i hope to have a look at image stacking, another way to counter the lack of DOF. By the way Roy you`ve got some nice macros yourself on your website. I particularly like the Bush Cricket. What lens did you use forr that ?

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I have had a play at image stacking on stationary objects Rob and it certainly works - how the heck some of these guys get a dozen or more exposures of a live insect at different focus points is beyond me.

The Bush cricket shot would have been with the Canon 100/2.8 macro.

rob lee said:

Which is why i was asking about aperture control to begin with. I will be photographing mainly (hopefully) still subjects & using a mini tripod so slow shutter speeds will not be too much of a problem. A lot of top macro shots are taken with shutter speeds of over a second. I have only used a compact before so dont know what the effects of mirror slap? might be. Camera arrived about an hour ago & am now waiting for battery to charge before i can start playing. As i get more proficient i hope to have a look at image stacking, another way to counter the lack of DOF. By the way Roy you`ve got some nice macros yourself on your website. I particularly like the Bush Cricket. What lens did you use forr that ?

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Hi Rob, I think I know what you are asking, but just to confirm:

You want to control DOF by physically stopping down the lens , even though the lens cannot communicate with the camera as you will be using cheap extension tubes that don't have electrical contacts between the lens & body?

I haven't used the type of tubes you are talking about, but have read about this on another forum.

This might not be recommended by the camera manufacturer but it could be worth a try:

With the camera switched on and lens attached, set the aperture in the usual way, then press the DOF preview button and at the same time unscrew the lens from the camera body. It works on my 40D with the same 50mm lens you have and you can see that the lens's aperture blades are held in the chosen aperture position. Then re-connect the tubes between the camera and lens.

As I said, this might not be recommended by Canon, but I'd be interested to see what others think about it. It might be the only way you have to control DOF with the tubes you have.

Best of luck,

Steve

edit, I presume that for macro work using the type of tubes you intend to buy, many photographers would use an old type (ie. legacy lens with built in aperture ring) which would make controlling the aperture a doddle. As others have said, focusing manually would be the way to go and perhaps use shutter priority to fine-tune the amount of light getting through to the sensor. A bit of trial and error will surely reap rewards. With the method I've suggested you would have to set the aperture at first then leave it set at that position for the duration of your shoot, which would surely not be too much of a problem in a 'studio' environment.