Cameras forum

General discussion

using 2x1 tele converter

by finkel13 / May 4, 2009 1:22 AM PDT

Does anyone have experience using 2x1 tele converters? I'm considering using one to extend my Canon 75-300mm lens that I use with my Digital Rebel.

Discussion is locked
You are posting a reply to: using 2x1 tele converter
The posting of advertisements, profanity, or personal attacks is prohibited. Please refer to our CNET Forums policies for details. All submitted content is subject to our Terms of Use.
Track this discussion and email me when there are updates

If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem. Also please exercise your best judgment when posting in the forums--revealing personal information such as your e-mail address, telephone number, and address is not recommended.

You are reporting the following post: using 2x1 tele converter
This post has been flagged and will be reviewed by our staff. Thank you for helping us maintain CNET's great community.
Sorry, there was a problem flagging this post. Please try again now or at a later time.
If you believe this post is offensive or violates the CNET Forums' Usage policies, you can report it below (this will not automatically remove the post). Once reported, our moderators will be notified and the post will be reviewed.
Collapse -
I wouldn't
by kalel33-20416052469708587370302374692233 / May 4, 2009 1:35 AM PDT

A 2x teleconverter will degrade the image quality of the photo, which would be bad for the 75-300 because it's already the worst telephoto zoom lens made by Canon, by quite a ways. Also, if you add a teleconverter and the largest aperture is above F5.6 then the Camera loses autofocus. Since your lens is F5.6 to begin with then adding any teleconverter will lose autofocus.

Collapse -
Thanks
by finkel13 / May 4, 2009 1:42 AM PDT
In reply to: I wouldn't

I was wondering about what would happen to the autofocus, but have heard conflicting answers. I tried a Sigma 1.4x converter in a photo store and the autofocus seemed to work fine. Why us the 75-300 lens so bad in your opinion?

Collapse -
It's not just my opinion
by kalel33-20416052469708587370302374692233 / May 4, 2009 2:32 AM PDT
In reply to: Thanks

A 1.4x teleconverter would only drop you're aperture by one stop, but if you zoom to 300mm(where largest aperture is F5.6)it turns into F8 which you would lose auto focus. You lose two stops with a 2x.

Read these threads on the 75-300, there's a reason it's so cheap.

http://www.clubsnap.com/forums/showthread.php?t=183024

http://forums.dpreview.com/forums/readflat.asp?forum=1029&message=30694478&q=canon+75300&qf=m

http://www.flickr.com/groups/canondslr/discuss/72157594232506681/?search=EF+75-300mm+f%2F4-5.6+III+USM

Here is a ton of consumer reviews on the lens, it received 5.6 out of 10. The 55-250IS and 70-300IS are much better than the 75-300.

http://www.fredmiranda.com/reviews/showproduct.php?product=18&sort=7&cat=27&page=2

Collapse -
Also, here's a professional review site
by kalel33-20416052469708587370302374692233 / May 4, 2009 2:47 AM PDT
In reply to: Thanks
Collapse -
Re: canon lens
by finkel13 / May 4, 2009 9:09 AM PDT

I have the Canon EF 75-300mm f/4-5.6 IS USM

Collapse -
Optically they're the same lens, only missing IS
by kalel33-20416052469708587370302374692233 / May 4, 2009 9:14 AM PDT
In reply to: Re: canon lens

The 75-300 was the first to get IS back in the mid '90s, and even the IS is not near as efficient as the current IS lens.

Popular Forums
icon
Computer Newbies 10,686 discussions
icon
Computer Help 54,365 discussions
icon
Laptops 21,181 discussions
icon
Networking & Wireless 16,313 discussions
icon
Phones 17,137 discussions
icon
Security 31,287 discussions
icon
TVs & Home Theaters 22,101 discussions
icon
Windows 7 8,164 discussions
icon
Windows 10 2,657 discussions

The Samsung RF23M8090SG

One of the best French door fridges we've tested

A good-looking fridge with useful features like an auto-filling water pitcher and a temperature-adjustable "FlexZone" drawer. It was a near-flawless performer in our cooling tests.