tc's and macro lenses.

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33L

33L

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Lee
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Hi All.

i have a 150mm Macro lens and tempted to get the 1.4x TC. However before i do just a few questions.

1. how will the TC affect the min focus distance if any.
2. do they affect the minimum aperture ( in know that it will effectively be a 210mm f/4 at it widest)
3. Will a TC have any effect on the magnification ratio. I.e. will it still be 1:1?

TIA
Lee
 
Lee,
1....minimum focus distance will remain the same but the working distance will be reduced by the same amount as the physical length of the T/C.
2....one stop of light will be lost but that's really not an issue as you rarely shoot wide open for macro work.
3....the maximum magnification will increase from 1:1 to 1.4:1.

I frequently use a 1.4 T/C or Life size converter with my Canon 180L and see no ill effects.

Bob
 
if you say if the working distance is reduced do for the same size image do you have further away or closer to the subject than without a TC (sorry if its a dumb question.)
 
Your working distance will be 1.4x longer if you want lifesize but if you use the shortest working distance then you'll have 1.4x lifesize.
 
gotcha! thanks guys - i think im gonig to buy a TC soon then!
 
Hope you don't mind tagging onto this thread.....

Whats the difference between a TC and an extension tube, whats the pro's & conn's, and which situations would I use one over the other?

Cheers,
Texy
 
a tele convertor increases the focal length of the lens, and the extension tubes reduce the minimum focus distance and also increases the magnification. it basically turns a normal lens into a macro lens.


someone will be able to expalin that a bit better!
 
Well Thanks to Wack61 i have aquired at 1.4 TC finally. Had a quick play with it today and while the working distance is improved, just the little xtra magnification is great at closest focusing.
 
Lee this is certainly an interesting idea that I had never considered. How did you find the DoF with the TC? Did it affect the already slim DoF as Raynox do for example?
 
33L said:
a tele convertor increases the focal length of the lens, and the extension tubes reduce the minimum focus distance and also increases the magnification. it basically turns a normal lens into a macro lens.


someone will be able to expalin that a bit better!
Click to expand...

In addition, a TC has a lens element while Ext. Tubes don't. I've also read that some cheap TC's have an adverse effect on the image quality while Tubes don't.
 
swag72 said:
Lee this is certainly an interesting idea that I had never considered. How did you find the DoF with the TC? Did it affect the already slim DoF as Raynox do for example?
Click to expand...

I havent really explored that element of it. however from what i remember there wasnt that much difference, however i dont shoot wide open when doing macro but the extender was more bought for insects and having that extra bit of working distance. I know its not true macro.

Another little note is that the sigma lens does not auto focus between .38m & .49m on the scale. irrelevent of what focus range lock you apply on the lens.

the focus speed does not seem to be affected. I cant test IQ as i dont have my 50D to hand at the moment and playing with the EOS 3.

Will do some experiments when the 50D comes back.
 
strobemonkey said:
In addition, a TC has a lens element while Ext. Tubes don't. I've also read that some cheap TC's have an adverse effect on the image quality while Tubes don't.
Click to expand...

Quite right there strbemonkey, it is a trade off for working distance but if i wanted extreme magnification i would go with extension tubes. which might be another purchase at a later stage.
 
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