Please help with extension tubes

[tmjjk]

I recently ordered cheap extension tubes just to get a feel for how they worked before purchasing the more costly set. I am not having much success using them at all. I could be making a very easily fixed mistake because I have never used or even seen them being used. I have researched the internet but no real answers to my issues so I really hope someone can help me. My images are coming out with a very small portion being in focus. I don't know if I am doing something wrong or if its just the equipment I purchased. I am using a 50mm lens? Some of these kinda look like I was using a lensbaby... really blurred and out of focus. Thanks for any help! (the tubes do NOT have electrical connections and I know I was warned about that) I must manually focus.

 

[480sparky41 40]

I'm going to guess you have the lens wide open. Looks like a DOF issue.

 

[tmjjk]

Agreed... is there a way to fix that? I cannot control anything through the camera.... duh, I can probably fix it before attaching right? Gonna go try right now!

 

[Railphotog]

Extension tubes don't have any glass, so their quality should not make any difference. As noted, setting your lens at a smaller opening should give you more sharpness. Of course you'll need more light to shoot stopped down.

 

[Overread17 5]

Are you a Canon or Nikon shooter?


Also shot 3 looks good with the minimal depth of field (just look at Mishes work to see that macro does NOT mean little apertures need to be used the whole time: Flowers through my eyes - a set on Flickr

But yes the issue you have is that the depth of field in macro is very very thin, especially if you shoot wide open (note this is the same of macro lenses as well).

 

[tmjjk]

I am shooting with a canon xs... and just purchased the 50mm 1.4 the tubes are in a set labeled 1,2, and 3. I also do not understand the lengths :/ My guess is the longer the length of the tubes, the closer I am going to get? I was guessing I was too close and placed only the tube labeled 1 and opened my reduced my aperture to f10... and I do not see a difference... should I go to f22... Thank you for any help. Sorry if I sound like a tool, I am just learning.

 

[tmjjk]

Are you a Canon or Nikon shooter?


Also shot 3 looks good with the minimal depth of field (just look at Mishes work to see that macro does NOT mean little apertures need to be used the whole time: Flowers through my eyes - a set on Flickr

But yes the issue you have is that the depth of field in macro is very very thin, especially if you shoot wide open (note this is the same of macro lenses as well).

These images are very similar to what I am getting Thank you for this link, she does beautiful work. I just thought I was doing something wrong. I have seem some extremely sharp insect images here and the focus seemed to touch a much larger area of the image... like the entire bug. I will keep shooting and reading. Thanks

 

[Overread17 5]

Few pointers:

1) If they are ultra cheap tubes they won't have electrical contacts (you can look inside the tube - if you see metal pins you've got contacts, if not you've got nothing and thus no control over the lens direct).

2) If you have no control over the lens you have two options. First shoot wide open - all the time. The second is to use the canon trick.
For this you put the lens on the camera as normal and then set the desired aperture you want to shoot at (I'd suggest between f8 and f13 - maybe f16. Any smaller and you'll get diffraction softening the photos). Then press and hold the depth of field preview button (that tiny button on the lens mount just under it). Holding that button down then press the lens release and remove the lens (remember you've kept the camera on the whole time). The aperture blades on the lens will remain closed until you mount it to an off camera and turn it on (where upon they'll flick open again).
You can then mount the lens to the tubes and shoot - but you will have a dark viewfinder because the blades are shut the whole time.

3) The rough maths for extension tubes is:
(length of the extension tubes in mm - divided by - focal length of the lens (in mm) + native magnification of the lens = magnification :1

Note that most general extension tube kits give around 65mm total length when used together - so you'll be getting just over 1:1 with all the tubes added. And yes the more tubes you add the closer your minimum focusing distance will be. Also the shorter your maximum focusing distance will be.