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Old Dec 15, 2004, 8:51 PM   #1
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Hi i have a 300D and a Sigma 70-300 APO Super Macro MK2 lens.

I am looking for an inexpensive 2x teleconverter.The one sigma makes doesnt seem to work with my lens(or so it says on (http://www.sigma-imaging-uk.com/a_pages/access.htm) this website.

Its mainly for shooting the moon.

Anyone had experience with these?


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Old Dec 15, 2004, 8:57 PM   #2
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ive found this one to be in my budget is this ok?

http://www.firstcall-photographic.co...converter.html




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Old Dec 15, 2004, 9:41 PM   #3
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i've also found something else a 3x converter



http://www.47stphoto.com/ketepro300af.html
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Old Dec 15, 2004, 10:28 PM   #4
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I guess you're all sleeping.I've decieded to get that from ebay.



http://cgi.ebay.co.uk/ws/eBayISAPI.d...36393&rd=1



Looks like a good choice
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Old Dec 15, 2004, 11:41 PM   #5
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If I am right that Sigma 70-300 APO is a f4-f5.6 lens so with the 2x teleconverter it will be working at f11(you lose 2 stops of light with a 2x converter), the Drebel will not auto-focus with a lens slower than aboutF5.6.

The teleconverter will work but you will be doing manual focusing with a rather dim viewfinder. Also there is image degradation when using a teleconverter, especially when using a lens not intended for use with an unmatched teleconverter.

http://www.photozone.de/2Equipment/easytxt.htm#Ztelel gives that lens a 3.21(average) optical rating, not sure how well it will fare witha 2xteleconveter.
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Old Dec 16, 2004, 12:00 AM   #6
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manual focus doesnt bother me and from reading about the sigma i've found out that its at its best at f11 anyways.i think im gonna give it a shot as i have found it rather cheap.

BTW would the 2x mean i will be getting 300x1.6x2 = 960mm ?

That will be sweet

The moon will look very very close and ath iso100 should be very very good.
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Old Dec 16, 2004, 12:08 AM   #7
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hehe yes your arithmetrickery is correct. :lol:960mm brings things close.

However the F11 is the effective aperture, not the actual, when the lens is set to f5.6. When stopped down to the realF11 you will be getting the effective light of about F22. :roll:

I'm using the Tamron 2x sp teleconverter wtih the Canon 100-300 f4-f5.6 usm and it can be done, but takes patience. Also things get very wobley, even using a good tripod with thatkind offocal length.:blah:


Quote:
Originally Posted by gaida
doesnt bother me and from reading about the sigma i've found out that its at its best at f11 anyways.i think im gonna give it a shot as i have found it rather cheap.

BTW would the 2x mean i will be getting 300x1.6x2 = 960mm ?

That will be sweet

The moon will look very very close and ath iso100 should be very very good.
[/quote]
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Old Dec 16, 2004, 12:17 AM   #8
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thanks for the info.26th is the next fool moon i'll give it a shot
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Old Dec 16, 2004, 12:21 AM   #9
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Speaking of Moon, that was one of my first trys last fullish moon, it has been cloudy here since.

Canon 100-300 F4-F5.6 usm at 300, with the Tamron 2x sp teleconverter. Unsharp and resize for the webapplied in photoshop cs.

Interesting I just looked at the exif info and it reportes the 300mm fl, but I guess it can'tsee the 2x tc

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Old Dec 16, 2004, 12:23 AM   #10
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well heres mine at 300mm(480) from the 28th nov
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