extension tubes help

[zeddy]

i recently got a cheap set of extension tubes i have tried to take some photos but they all turn out blurred even when using a tripod,could someone give me some tips on how to get the best out of them, what programme do you shot in eg T.V or P any advice would be help full
thanks zsolt

[Oscar]

What camera are you using Zeddy? And what lens?

I used manual mode when I had a loan of an extension tube.

I also turned off the auto-focus and moved in or out to find the correct focal point. I was using the D70 with a 50mm lens. I found the auto-focus was continually hunting with every minute move in or out of the focal point - that is why I turned it off.

Got a few good keepers (for me anyway) that way.

Cheers, Mick

[zeddy]

i am using a canon 30D with the kit lens 18-55mm no auto focus as they are cheap tubes no communication with lens
thanks zsolt

[gstark]

How does the proposed image look through the viewfinder when you're composing the image?

What shutter speeds and aperture settings are you using?

[zeddy]

the image looks fine through the view finder,how do you adjust the aperture is it done by setting the aperture in A.V mode then remove the lens and fit the tubes in? if yes then it was at f22 and shutter speed was at 1/250

[phillipb]

Zeddy, if they are as you say old tubes, then you will need to use them with the camera in manual mode, because there won't be any contacts on them to relay information to the camera.

[stetner]

Hi zeddy,

The lens does not close down unless you push the DOF preview button on the front lower left when holding the camera. (Edit: I don't think your 18-55 will be any different to my 17-85 in this regard, I could be wrong)

On my 20D the lens also opens back up when the camera is turned off.

I think you would need to set it in AV mode, hold the DOF preview button, and then take the lens off.

BUT, whether or not this is good/bad for the lens/camera is a different story. Maybe someone else knows, but I would tend to spend a few more dollars to get tubes that worked.....

[Ronza]

Put the camera in Av, stop the lens down with the DOF preview and remove it. Attatch said lens to camera. Camera shall meter fine in Av mode. Only problem would lie in composing an image with the lens stopped down - it gets a wee bit dark.

I used the method for a while and AFAIK, my 50/1.8 is still good

[gstark]

Sounds like a hell of a way to work.

I'd probably be inclined to follow Petal666's advice, and invest in a more compatible set of tubes.

Answering your question: I think the technique involved is dooming your results from the start. You're pushing rope.

[Matt. K]

F22 at 1/250 with extension tubes does not sound right unless you are shooting at ISO 3200. You lose a lot of light through those tubes so at f22 @ ISO 200 exposure should be around 1/8th of a second to about 1/30 depending on light.

[Mr Darcy]

With manual tubes on a modern camera, you would probably be better off shooting with the lens wide open. This is its default state, and will simplify adjusting things. Use Shutter speed and as a last resort ISO to control exposure

I haven't used tubes since my Pentax Spotmatic F days (mid 70s) , but I dimly recall I had no problems with wide open lenses, as with tubes you are essentially looking at the centre of the image anyway, where the lens designers put most of their effort into quality.

For exposure, start with what the meter says with just the lens, then reduce the speed until you get good exposures with your tubes. Remember the correction (write it on the side of the tube!) and apply it whenever you use the tubes. If you have stacking tubes, don't forget that each combination will have its own correction. If you have helicoid tubes, it will be difficult. Maybe get a ball park at each end of its extension, then guess and use PP to do the final correction.
Use a static object about the same size as your planned object for your tests e.g. if you want to shoot mosquitos, test with a pin stuck in a board. If you want to shoot orchids, use a crumpled up sheet of paper.

Alternatively, as said esewhere, buy better quality tubes.

HTH Greg

[zeddy]

thanks for your tips will have a play on the weekend and try all your suggestions
thanks zsolt

[moz]

And good luck manually focussing the 18-55 kit lens. I tried it once, it's no fun at all. There's not a lot of rotation between minimum focus and maximum, plus the front element moves in and out (as well as rotating) when you focus so macro would be even more exciting. I'd be tempted to duct tape it at 55mm/minimum focus distance and move the camera.

[zeddy]

well i went out and had a play this time using a 75-300mm lens i am not really happy with the results here are some sample these are the best i could get






thanks zsolt

[Matt. K]

What F stop did you have set on your lens? When doing macro pics you should set f11 or f16 or even f22 if your lens has it.

[zeddy]

mate i reall dont know i set the lens up on the camera to f32 then took the lens off and put the tubes on
thanks zsolt

[DANTPR11]

G'day Zeddy, I'm not too sure if the problem you are having may be with the cheap tubes themselves, I know they are just a spacer between the lens and body so maybe your problem may have something to do with the distance these tubes separate the lens from the body.
These 2 shots are ones I took using my Canon ext. tube, the biggest problem I have had to date is using it creatively and finding subjects to use it with.....I just wish I had never deleted my shots I had of a huntsman spider from 5mm distance, it looked like something from outerspace

This is a pretty major crop just to get a bit more detail from the fly
I was using f9, 1/250, iso400 at 300mm


This one of a chain I used f5.6, 1/100, iso 400 at 250mm

[Matt. K]

The length of the tubes have no bearing on the quality of the image. More length simply means more magnification. The problem is a depth of field problem and when using macro tubes you should be using very small F stops in order to maximise DOF. Using extension tubes with the lens wide open can result in a plane of sharpness less than 0.25mm, which is what we are seeing with the image in question. I also suspect we are seeing just a little camera movement and this also has reduced the overall sharpness of the image. I would suggest using ISO 400 @ f22 and a very sturdy tripod and a remote shutter release for all macro work. Hand held macro will always be hit and miss unless electronic flash is your main source of light.