 Robert |
Using Teleconvertors Hello all, I'm new here and hope I'm not beating a dead horse, but I haven't been able to find my answer yet. Anywho, I use a 2x converter on my Minolta X700 with my 28-210mm lens. The lowest f# is 22. With my understanding of teleconverters, I would think that would change the lowest f# to 45. Can anyone verify this for me? I appreciate the help, Robert
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Terry R. Hatfield |
Hi Robert!Teleconverters Are Used to Increase Your Focal Length Of The Lens You Are Using,It Will Not Change Your Fstops However You Will Lose 2 Stops Of Light On The Max Aperture End (Small F#'s)It Will Have No Effect On The Min Aperture(Large F#'S) Im Not Sure What Your Max Aperture Is On That Lens?But Just Add In A 2 Stop Loss, If It Was A 2.8 Max Aperture That Would Make Your Max Aperture F5.6, At Longer Focal Lengths You Must Use A Tripod To Prevent Camera Shake And You Will Have A Loss Of Detail Even With The Very Best Tele's, I Would Suggest A 1.4x Tele Over The 2.0x You Lose Only 1 Stop With These And Have More Detail, Hope That Helps:-)
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Bob Cammarata |
The ratio of loss you are describing with a 2X, is based upon light actually reaching the film plane. At all apertures, you will need a shutter speed which is two stops slower than with the same lens without the converter attached. Don't be mis-led into thinking that your depth of field will be greater with the tele-converter....(It will actually decrease.)
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Terry R. Hatfield |
Hi Bob!Yes Thats What I Said:-) It Will Lose 2 Stops Of Light Thus Preventing Your Lens From Reaching Max Aperture.Here Is an Example Robert; The Depth of Field of a lens + TC is exactly the same as the depth of field of an equivalent prime lens at the same aperture. So a 300/2.8 with a 2x TC (600/5.6) will have exactly the same depth of field wide open (f5,6) as a 600/5.6 lens at f5.6 (or a 600/4 shot at f5.6) And Another:-) If you add a 2x TC to a lens and don't change your distance from a subject, your magnification will double and your depth of field will decrease - in fact for most telephoto subjects it will be approximately cut in half Anyway Robert Was Asking If It Changed The F#s If I Read His Question Correctly?It Will Not Change Your Min F#s(Larger#s) From F22 To F45 And Shutter Speed Was Never Part Of His Question! Hope Your Not To Confused Robert!LOL!!
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Robert |
Not confused at all. That was quite helpful. I appreciate all of your answers. Now I know what to expect when using the TC. Thanks again, Robert
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