Experiments with a Canon 1.4 extender.

petersmart

petersmart

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Recently I have been experimenting with fitting a 1.4 extender to my 70-300mm IS USM lens.

Normally you cannot fit the 70-300mm lens to any Canon extender because there is not enough clearance between the lenses so I fitted a 12 mm Kenko DG AF extension tube between the extender and the 70-300mm lens, an idea I saw on here a little while ago.

This meant the lenses would not hit each other and get damaged.

The only 2 real drawbacks are that you cannot focus beyond about 50-60ft and the AF does not work properly so you have to use manual focus.

However as an experiment I am very pleased, and surprised, at the results which are shown here:

http://www.flickr.com/photos/20926615@N05/sets/72157624752207271/

The sparrows were on a bush about 50ft away from my landing window.

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Nice!

I like people who think outside the box a little bit. :thumbs:
 
trencheel303 said:
Nice!

I like people who think outside the box a little bit. :thumbs:
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Thanks trencheel - must admit I was quite surprised at the quality because although the 70-300mm IS USM lens is quite sharp it does get little soft at the far end so I didn't expect to get the sharpness I did.

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petersmart said:
Well as a rough estimate - I'm not very good on judging distances.

Why?

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50 ft is a long way in sparrow photography terms and so i was wondering how much of a crop your images are. If they are big crops and still look good then full frame shots will be even better
 
paul_g said:
50 ft is a long way in sparrow photography terms and so i was wondering how much of a crop your images are. If they are big crops and still look good then full frame shots will be even better
Click to expand...

This is the complete image before cropping:

07611.jpg

As I say I'm not very good at judging distances but no doubt some clever person can use maths to work out the exact distance away based on the size of the sparrow and the crop factor of the camera which is 1.6.

I was just trying it as an experiment which I'm very pleased with and perhaps it will stimulate others to also go outside the box a bit.

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For that shot at 480mm, you are looking more like 15 feet.

Which in itself is a good show for sparrows. Nice shot.
 
RichardtheSane said:
For that shot at 480mm, you are looking more like 15 feet.

Which in itself is a good show for sparrows. Nice shot.
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The adjusted focal length of the lens would be 420mm.

But the distance is certainly longer than 15 feet - I'd say a minimum of 25 feet.

Thanks for the compliment.

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You are right, I was using 1.6 instead of 1.4, Ooops.

I used this for an approximation of distance.
http://www.giangrandi.ch/optics/lenses/focalcalc.html

From personal experience - the distance between my back door and the back of my garden where the birds sit is 25 feet. I use a 300mm prime with 1.4x convertor and if a small bird is at the back of the garden there is no chance I will get a shot as good as yours - definitly not as frame filling.
 
RichardtheSane said:
You are right, I was using 1.6 instead of 1.4, Ooops.

I used this for an approximation of distance.
http://www.giangrandi.ch/optics/lenses/focalcalc.html

From personal experience - the distance between my back door and the back of my garden where the birds sit is 25 feet. I use a 300mm prime with 1.4x convertor and if a small bird is at the back of the garden there is no chance I will get a shot as good as yours - definitly not as frame filling.
Click to expand...

I'll have to actually try to get a rough measurement.
 
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