| Author | Thread |
|
|
08/18/2005 09:05:27 AM · #1 |
Hi. Just doing research on what I am saving up for... One day when I'm rich and famous, I will buy myself a 20D. I would probably do well to get a few lenses as well. I will continue to do more research on lenses for a while. In the meantime, I have this to ask...
I would like to know what effect the teleconverters have on lenses. How they effect the following characteristics.
- Sharpness
- focus at infinity
- minimum focal length
- Macro abilities of macro and non-macro lenses
I have read that most lenses lose softness at around the top 25% of their focal range and this problem is exacerbated with the TC. This would therefore make the thing largely useless, capable of allowing you take closer, but crummy shots. This is obviously based on what I have read and not on use.
I currently am learning a lot from my S2 which has taught me that lenses are typically good either close or far, no lenses are good both ways.
My list of desired lenses so far would be:
Canon 50mm 1.8
Canon 100mm 2.8macro
Tamron 24-70 2.8
Sigma 70-300 f3.5-5.6 Super Macro II (It's $139)
Sigma 80-400 OS 4.0-5.6 for the future when I'm REaLLy rich and Really famous... and actually know a bit about how to use the darn things :)
Comments on the lenses themselves is welcome, but I am not really decided on anything beyond the two primes and the cheap Sigma zoom, so that is not my purpose in this thread.
Would like to know if either teleconverter is worth anything with this set of lenses.
I also heard that the TC disables some control of the lens in the 20D. |
|
|
|
08/18/2005 09:08:05 AM · #2 |
The Canon teleconverters won't work on any of the lenses you've listed. It tends to be longer range Canon L lenses.
You will likely be able to use third party converters, however.
|
|
|
|
08/18/2005 09:26:51 AM · #3 |
Wow, uhh thanks!
Are Macro converters the same as tele converters?
What are good third party converters that will work with these lenses?
What effect will they have on them?
What aspects of control will I lose?
What aspects of control will I keep? |
|
|
|
08/18/2005 09:40:40 AM · #4 |
TCs the Basics...
Generally with a 1.4x TC you will loose an f/stop and with a 2x you will loose 2 whole stops. My 20-700mm 4L becomes a 5.6 when attached to a 1.4x TC. I have had no problems with that combo.
Arps of 6.3 and better I have noticed with other higher min f/stop that AF starts to hunt. With a 2x AF might not work at all, you need really fast lenses for these guys.
I use a Kenko Pro 300 DG 1.4x (which is the same as the Tamron both using the same hoya glass). All my canon lenses EXCEPT the EFS mount kit lens fit this convertor. I know the Kenko reports proper EXIF to the 20D, I have heard there are other generics that don't.
I have not noticed any sharpness lose on my 70-200mm 4L or my Tamron 28-75mm 2.8, put a soft lense on a TC and well you know what you get.
ED: dyslexia
Message edited by author 2005-08-18 09:43:08.
|
|
|
|
08/18/2005 09:40:41 AM · #5 |
Teleconverters 1.4X and 2X work best on fixed lenses such as the Canon 300mm, Canon 400mm Canon 500mm (or equivalents in other brands). While you can use them with zooms such as the Canon 100-400mm lens - the 1.4X will let you use autofocus using the center spot, the 2X will not autofocus with the 100-400mm. I found that the teleconverters worked best when the subject was not too far away and filled the frame. You also lose light gathering capability - so it also works best in shots where you have bright light.
Extension tubes (used for macros) are entirely different. There is no glass - so it does not degrade the quality of the image. They can be stacked. However, the closer you get to your object, your depth of field becomes very shallow. I've used extension tubes on my 100-400 and on my Tamron 200 macro lens successfully. |
|
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 09/18/2025 06:10:58 PM EDT.
