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300mm + 2x Converter =?  
User currently offlineAA 777 From United States of America, joined May 2002, 807 posts, RR: 13
Posted (11 years 4 months 4 hours ago) and read 1993 times:
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Hello everyone,

When you put a 2x converter on any lense does it double it? For example would a 300mm + 2x Converter = 600mm?

AA 777
Matt


CRJ-700 FO
9 replies: All unread, jump to last
 
User currently offlineWietse From Netherlands, joined Oct 2001, 3809 posts, RR: 56
Reply 1, posted (11 years 4 months 3 hours ago) and read 1961 times:

Yes...

but it also doubles your apperture (makes it less light sensitive)

So a 75-300mm F4-5.6 lens becomes a 150-600mm F8-11.2 lens... wouldnt want that... Smile

Wietse



Wietse de Graaf
User currently offlineMirage From Portugal, joined May 1999, 3122 posts, RR: 15
Reply 2, posted (11 years 4 months 3 hours ago) and read 1954 times:

This one was at 600mm, using a Canon 75-300 4.5-5.6 and a Canon 2x teleconverter.


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Photo © Luis Rosa



Luis


User currently offlineClickhappy From United States of America, joined Sep 2001, 9601 posts, RR: 69
Reply 3, posted (11 years 4 months 3 hours ago) and read 1934 times:
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PHOTO SCREENER

and of course, with the Focal Length Multiplier Factor of a DSLR you can add x1.5 for a D100, x1.6 for a D60, and x1.5 for a S2.

User currently offlineCkw From UK - England, joined Aug 2010, 713 posts, RR: 16
Reply 4, posted (11 years 4 months ago) and read 1842 times:

DSLRs have a CROP factor, not a focal length factor ... there is a big difference. The crop factor of a DSLR is exactly the same as enlarging the central portion of a 35mm - it does not decrease the depth of field or add the optical compression effect of a true focal length multiplier (such as a teleconvertor) - a picture taken with a 400mm on a DSLR (with a crop factor bringing it up to 600mm) is not the same as a shot taken with a 600mm on a 35mm.

Cheers,

Colin



Colin K. Work, Pixstel
User currently offlineClickhappy From United States of America, joined Sep 2001, 9601 posts, RR: 69
Reply 5, posted (11 years 4 months ago) and read 1831 times:
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PHOTO SCREENER

you are correct  Smile

http://www.dpreview.com/learn/Glossary/Optical/Focal_length_multiplier_01.htm


User currently offlinePhotopilot From Canada, joined Jul 2002, 2629 posts, RR: 18
Reply 6, posted (11 years 3 months 4 weeks 1 day 21 hours ago) and read 1819 times:

One slight correction of what Wietse says.

A tele-converter does not "double" the aperature of a lens. It adds effective f:stops. A 2x converter adds 2 f:stops to the exposure. Therefore a 75-300mm F4-5.6 lens becomes a 150-600mm F8-f:11 lens... not 11.2

A 3x converter generally adds 3 f:stops. eg. a 2.8 lens will become an f:8 lens.

Each converter comes with an exposure compensation value written down somewhere in the instructions. At least it should, though with through-the-lens metering this generallly isn't a problem. It is only us guys that use a hand-held incident meter that have to take this into account.

One other thing. Converters tend to break down in quality most noticeable at the frame corners first. With the "crop" factor of DSLR's, this doesn't affect you as soon. Another benefit to DSLR's.

Hope this helps.

Steve


User currently offlineJwenting From Netherlands, joined Apr 2001, 10213 posts, RR: 19
Reply 7, posted (11 years 3 months 4 weeks 1 day 9 hours ago) and read 1770 times:

Correct Steve. DOF stays the same too (so you get f/8 with the DOF you'd get at f/4 when selecting f/4, but the amount of light needed doubles.


I wish I were flying
User currently offlineCkw From UK - England, joined Aug 2010, 713 posts, RR: 16
Reply 8, posted (11 years 3 months 4 weeks 1 day 8 hours ago) and read 1770 times:

Another thing which stays the same is the minimum focusing distance - this can be a real boon if you're into insect or flower photography. My 300mm has a so called "macro" capability, which is OK - but stick a 2x convertor on it, and I've got both a much more powerful macro capability PLUS the ability to work at a comfortable distance from the subject ... and, because I could be a meter or more from my subject, I can easily use fill-in flash if necessary.

Cheers,

Colin



Colin K. Work, Pixstel
User currently offlineLugonza_2001 From Spain, joined Oct 2001, 315 posts, RR: 1
Reply 9, posted (11 years 3 months 3 weeks 4 days 17 hours ago) and read 1712 times:

One important thing, i believe that when you use a convertor, you lose the auto-focus capability.

Best regards

Luis


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