Tips for Extension Tubes with EOS 90D

[Ramsden]

Hi Folks 

Last year, while reading Bryan Petterson's Understanding Composition, I purchased a 23mm Extension tube to take close ups of mainly flowers and plants in my garden, and on walks. I used it mainly with a 50 Prime on my EOS90D. Since last year I've bought a 75-300 zoom and it fits that beast as well - but it's a handfull.

I'm using a tripod but focussing is still a fine art.

Any friendly tips on 

1) using extensions and should I buy a bigger set?

2) and other things than flowers for getting creative

Ramsden

[p4pictures]

I have the Canon 25mm and 12mm extension tubes. The more extension you use the closer to the subject the lens has to be. For a shorter focal length lens this might even move the point of focus within the lens itself. 

There is some loss of light from using an extension tube, but you don’t see the reported aperture decreasing. Also the longer the tube the more important is the optical quality of the lens you use, as essentially you are only capturing the scene from a smaller part of the lens. I’ve used my tubes with a 90mm TS-E lens to good effect! 

With your EOS 90D I’d use live view and enable focus peaking to help you see where the focussed part of your subject is. 

Any subject where you isolate hidden or less commonly seen details can be an interesting subject. You might also want to consider a macro lens at some point. The EF 100mm f/2.8L Macro IS USM is a great lens on your EOS 90D, but you can also get the EF-S 60mm f/2.8 Macro USM for great prices if you buy a good used example.

[Ramsden]

Thanks Brian

I’m a big fan of 50mm Macro so happy to increase my range. Your information on the focus point now makes sense and help me understand the changes to handling the camera. In previous posts some guys have suggested getting rid of my Macros and getting a Sigma ??? - but I think the quality of my Macro shoots is very satisfying to my untrained eye.

Regards

Ramsden

[Waddizzle]

The ideal size of an extension tube depends upon the focal length you’re using.  You want your total length of extension tubes, mm, to be 25-40% of the focal length of the lens.

Any shorter than that, and the magnification may not be noticeable.  Any longer than that, and you may run the risk of the maximum focus distance being inside the lens barrel, as Brian noted above.  

The 70-300mm is probably too long for extension tubes.  Besides, its MFD is too long out of the starting gate.  

[Ramsden]

Thanks Waddizzle. The ratio is a useful bit of information. I agree entirely about the big lens, it was an interesting 30 mins in my garden, which I'm sure amused my neighbours! 

Best

Ramsden