Teleconverters noobie questions


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etegration

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Oct 14, 2003
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#1
hi, if say i get a 18-200mm lense and a 2x teleconverters, effectively, the minimium i can go will become 18x2=36mm right?

where does the teleconverter fit?
1. camera body > tc > lense or
2. camera body > lense > tc?

if it's 2 then it'll be easy for me to take away the tc when i need 18mm with something wider right? but if it's 1, then gonna dismantle and fix again, gonna waste time and may miss shots.
 

DarNikon

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Nov 8, 2005
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#2
etegration said:
hi, if say i get a 18-200mm lense and a 2x teleconverters, effectively, the minimium i can go will become 18x2=36mm right?

where does the teleconverter fit?
1. camera body > tc > lense or
2. camera body > lense > tc?

if it's 2 then it'll be easy for me to take away the tc when i need 18mm with something wider right? but if it's 1, then gonna dismantle and fix again, gonna waste time and may miss shots.
Hi there
Unfortnately, the answer is 1. However, not an issue since it can be removed easily. Think it's about deciding what you want to shoot, if you think your subject would be in the wide range,then remove the TC in the first place. I suppose your TC is intended to increase the zoom factor of your shot.

Also, since the TC has a glass element, choose kenko or better known brands.

cheers
 

Denosha

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#3
Hmm... i'd like to point out that using a 2x TC on a 18-200 would mean no AF + probably horrid image quality. I wouldn't bother if I were you.
 

smtan24

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Dec 21, 2005
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#4
What is the F stop for the lens? Usually if its below F2.8 the auto focus will not work and as they stated the image will not be so good.
 

Jul 31, 2005
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#5
smtan24 said:
What is the F stop for the lens? Usually if its below F2.8 the auto focus will not work and as they stated the image will not be so good.
hav u actually personally tried using tele converters? i used afs300/4 with tc1.4 before and the af is only slightly slowed down. i dont see any difference in quality till i blow up to 200%

and since when was there a 18-200/2.8?
 

Jul 31, 2005
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#6
Denosha said:
Hmm... i'd like to point out that using a 2x TC on a 18-200 would mean no AF + probably horrid image quality. I wouldn't bother if I were you.
yea, for the price of a tc, u might as well get a 70-300
 

Jul 31, 2005
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#7
DarNikon said:
Also, since the TC has a glass element, choose kenko or better known brands.

cheers
slr tele converters hav more thn 1 element unlike consumer [screw-in] converters. the most impt thing when choosing tc is to check the compatibility, u may get af with some tc but not others for example.
 

Denosha

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#8
roti_prata said:
hav u actually personally tried using tele converters? i used afs300/4 with tc1.4 before and the af is only slightly slowed down. i dont see any difference in quality till i blow up to 200% and since when was there a 18-200/2.8?
The 1.4x TC only adds one stop so your lens will still AF (F5.6). 18-200s are like 3.5-5.6/6.3 and a 2x TC adds 2 stops so that ends up as F7.1-F11/F13. I've tried a 2x TC on a 70-200 F2.8 and it's hopeless. I've also tried a 1.4x TC on a Bigma (F4-6.3) and it won't AF at all. Image quality is also hopeless.

Anyway, just a tip. Non-Sigma TCs won't AF with Sigma HSM lenses (verified this myself at TCW using a kenko TC on a Sigma 70-200 F2.8 EX HSM).
 

Jul 31, 2005
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#9
Denosha said:
The 1.4x TC only adds one stop so your lens will still AF (F5.6). 18-200s are like 3.5-5.6/6.3 and a 2x TC adds 2 stops so that ends up as F7.1-F11/F13. I've tried a 2x TC on a 70-200 F2.8 and it's hopeless. I've also tried a 1.4x TC on a Bigma (F4-6.3) and it won't AF at all. Image quality is also hopeless.

Anyway, just a tip. Non-Sigma TCs won't AF with Sigma HSM lenses (verified this myself at TCW using a kenko TC on a Sigma 70-200 F2.8 EX HSM).
who say must use tc2.0?:bsmilie: tc1.4 and 1.7 r wat ppl normally use, 2.0 degrades too much. the bigma by itself is already not very good optics and u want to tc it somemore cfm die 1 wad
 

Canew

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Jul 26, 2005
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#10
OT abit: For everyone's information: the TELEPLUS 1.4X 300 PRO works very well with the EF 70 - 200 f/4 L. AF is not compromised nor quality.
 

Denosha

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#11
roti_prata said:
who say must use tc2.0?:bsmilie: tc1.4 and 1.7 r wat ppl normally use, 2.0 degrades too much. the bigma by itself is already not very good optics and u want to tc it somemore cfm die 1 wad
I'm replying to you in the context of the original question asked by etegration, otherwise would be OT no? He asked specifically about a 2x TC and a 18-200 (which in terms of aperture and optical quality is sorta similar to the 50-500) so I'm just sharing my experience with him based on what you brought up.

Anyway, yeah, you're right. That's why i sold off my 2x tc and got a 1.4x instead to use with my primes and 70-200L IS. ;p And I thought I could get a usable 400 F5.6 with a 2x TC + Sigma 70-200. Boy, that was a waste of $$$ :(
 

justarius

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Nov 9, 2003
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#12
General rule of thumb is if the effective aperture of your lens is greater than f8 after adding the TC, it would become too dim for the AF to work properly, thus losing autofocus. Thus max aperture of your lens before adding a 2X TC should be f4 or bigger. And as the others have said, the optical quality of a 18-200 is already quite dubious, and you want to enhance all the flaws by magnifying it 2 times more? TCs are better used on primes or the professional quality f2.8 zooms, rather than the consumer range of lenses.

Another factor is that wide zooms are usually not suited for TCs, as the rear glass might actually bang into the TC while you zoom in and out. Nikon does not recommend using TCs on all of their wide zooms, as the at the wider range, the rear glass will bang into the TC.
 

Jul 31, 2005
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Bt Batok
#13
i dont think any current 18-200 lenses(including the nikkor) can be used with tc without losing af and maybe metering
 

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