A Traveler and his Cat exploring America.

Wednesday, April 4, 2012

The Tele-Extender

Yesterday I posted a few pictures of a Golden-Crowned Sparrow for World Bird Wednesday (you can view those pictures here). He just happened by while I was experimenting with using a 2X tele-extender I've had for a few months but never used. I had a few inquires about the extender so thought I'd devote today's post to it. I get asked questions which I am all too happy to answer but when your e-mail comes in with an address JoeBlow(noreply-comment@blogger.com) I am unable to get back to you. You may want to consider changing that in your settings.

The extender is a small attachment lens that fits onto the camera on which the lens attaches to. Mine is a 2X which means it doubles the power of the lens thus a 300mm will now be like a 600mm. They come in 1.7X and 1.4. These two will produce slightly sharper images but at less magnification.

My first try with the extender was giving me over-exposed images. You'd think with less light getting in they would be under-exposed but such is not the case, at least for me. I had to fool the camera and adjust it to one full stop over which is what I found to work best. I also had the ISO set at 800 (any higher may produce graininess). My 70-300mm lens is a f5.6 at it's widest open aperture. With the ISO set as it was I was able to have the aperture at f7 or f8 it's mid-range which experts say lies the "sweet spot" with most lenses.

Having these settings in place the shutter speed was no lower than 100th of a second. A tripod is a must when using a tele-extender. I found just touching the shutter release button caused the camera to bounce so for best results I used my remote shutter release.

Finally, I lost the auto-focus feature with the tele-extender in place. I knew this beforehand. It's a Nikon thing or the vibration reduction lens, I forget which. Know this too, pictures taken with an extender in place will not be as sharp was with the lens alone. This makes you consider What if I just crop (or blow up) a regular image instead? With the multi-pixels of cameras these days this may be a better way to go. I need to experiment more with this in mind.

Here are some comparisons as to what the 2X extender along with my zoom set at the max (300mm) can do. The first picture is normal at what the eye sees.
The house on the hill.
The street sign, how clear would the letters be.

As I closed my post yesterday, "Overall these aren't too bad considering pushing the equiptment as I was. I think with a little more practice I can get some improvements. This is not a combination I would use very often but it is nice to know it does work and may come in handy when that day arrives that I spot my first Desert Big Horn Sheep high up on a rocky crag of a desert mountain."


  1. it really is amazing - the street sign is a great example.

  2. Unless I duct-taped one of these babies to my camera, I doubt I will ever get the opportunity to use one! ;) It definitly makes a big difference!

  3. a good example of the tele extender John. Which one are you using?
    Valleys ShutterBug

  4. Lovely images John... I have tried them in the past... with no real success apart from making a decent profit selling them on Ebay.

  5. Wonderful information, John! I can hardly wait to go out and try it now...with the tripod and the remote release! Thank you so much for the assistance!

  6. Not bad at all. Don't get caught spying on the neighbors with this set up. ;^)

  7. I'm liking where you're going with the new equipment John; great examples! Stick with it and I look forward to seeing how it does for you out in the field...


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