Tubes usage question

[JohnN]

Hi all,

I picked up some cheap tubes (£5 or some such from ebay - I know not the best by far but I wanted to experiment before getting something meatier).

Now this is the image I get without tubes:

In case you're wondering its a pomegranate seed.

I then attach my smallest tube "1" and get this:

Then with all three:

The problem I have was the distance I had to get (using my EFS 18-55mm - haven't tried any other lenses yet)

I had a bash and read all sorts of things about stepping forward and back to get focus and so on, but the only place I could focus was 2cms away or so!

Any ideas where I'm going wrong or will I have to drug any insects I want to shoot

 

[The23rdman]

Tubes give a rediculusly narrow DoF. What aperture did you have it set at?

 

[JohnN]

Before I put the tubes on it was f/5.6 and I left it n manual so I assume it stayed that way.

 

[bartoszwozniak]

I have just checked your EXIF data and your aperture was f/5.6 on the photo without tubes (cant check the other ones) You really need to shoot a little narrower in order to get your DOF a little deeper. Something like f/11 would be a good starting point

Bart

 

[JohnN]

Excellent - I'll give that a shot later.

Will that help with the range issue?

Also would using a longer lens help (such as a 55-250?)

 

[jomike]

With the cheap tubes you have there is no electrical contact between body and lens, that means you cannot change the aperture from the body normally. (Canon uses electric motor aperture control).

There is a way to change the aperture, mount the lens on the camera with no tubes, choose an aperture value of about f/10, then press and hold the DOF preview button and remove the lens. Now the lens will be stuck in f/10 and you will get better DOF when you mount the lens with tubes. You will probably also need flash to get adequate exposure.

This will not help with your working distance between end of lens and subject. For that you need longer focal length.

 

[JohnN]

That is brilliant - thank you all.

I just tried my 55-250 and didn't have to climb up anythings nose for it to work!

Here was the shot with just the EFS 55-250 (f13) - with built in flash:

The with all three tubes (f10) locked using DF button advice and for this I must have been 80cms away or so:

I did notice too what people say about the lighting:

With tubes & flash at about 1m:

Same(ish) picture without the tube and with flash:

So I can see that if I wanted to get really close I would need and external flash to get round the tubes blocking the in built flash.