Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Canon Lenses

Reply
 
Thread Tools Search this Thread
Old May 25, 2007, 4:11 AM   #1
Junior Member
 
Join Date: Jan 2007
Posts: 23
Default

Need a little help and explination, I have a 70 - 200Canon IS lens really pleased with it shots are outstanding, I use it pretty much only forreptiles the only adition I could think of to my kit would be a TC or ETmaybe canon or another make to be on the cheap side ? Im going to be in singapore in 3 weeks so I could find a bargin, worth going for a different make other than canon ? Also extention tube it would be real nice to have the ability to focus closer some times I naturally find my self walking up on a subject and ended up to close but then im not used to this lens yet, but macro would be nice. TC will allow closer focusing or just extention tube? what will I loose some quality on the TC what about the tube must compramise something?

any suggestions on adding to my kit ?
RichUK is offline   Reply With Quote
Sponsored Links
Old May 25, 2007, 5:58 AM   #2
NHL
Senior Member
 
NHL's Avatar
 
Join Date: Jun 2002
Location: 39.18776, -77.311353333333
Posts: 11,547
Default

TC has glass in them so the resulting lens/TC will vary depending on their combination as some TC has more elements in them (also thicker) than others... More glass (usually cost more) means better correction but at the expense of contrast.

Tube on the other are passive as the only thing between the lens and the camera is empty space so a more expensive tube will not affect the behavior of a lens any as the quality of the air is the same

Tube alters both the minimum and maximum distances - TC on the other hand magnifies the image, but does not vary the minimum distance... In one case you are changing the magnification by physically getting closer on the other you stay fix but the magnification is modified by the amount of glass inserted...
TC is beneficial in the case you can't get closer -> more equivalent to a longer macro where the subject tends to escape away. Tube(s) on the other hand preserves the quality of the glass as nothing really has changed optically, but remember your lens does not behave as normal anymore unlike a TC, you must remove the tube(s) to take picture of longer shots - You can keep a TC on the lens all the time as the other benefit
NHL is offline   Reply With Quote
Old Jun 6, 2007, 1:40 PM   #3
Junior Member
 
Join Date: Jan 2007
Posts: 23
Default

thanks, Ill take a look at whats on offer when Im away, Im still abit lost on the whole tube thing, do all tubes allow the lens to talk through for autofocus etc? how big a tube do you need to know where you can focus from? guess depending on the lens!
RichUK is offline   Reply With Quote
Old Jun 6, 2007, 2:40 PM   #4
NHL
Senior Member
 
NHL's Avatar
 
Join Date: Jun 2002
Location: 39.18776, -77.311353333333
Posts: 11,547
Default

Some do AF and some don't - You'll need the ones with the visible electrical contacts inside:
http://www.thkphoto.com/products/kenko/slrc-04.html

-> They are stakable so the resulting lenghts will vary...
NHL is offline   Reply With Quote
Old Jun 10, 2007, 5:05 AM   #5
Junior Member
 
Join Date: Jan 2007
Posts: 23
Default

Thanks NHL, Checking them out :-)
RichUK is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 6:20 PM.