| Author | Thread |
|
|
12/22/2005 03:29:34 PM · #1 |
A generous friend has loaned me some toys to play with for a few weeks - a Tamron 1.4x TC and a Tamron 2.0x TC.
I tried them both and here are some samples:
210mm f4 (effective 336mm)
294mm f4 (210 + 1.4TC) (effective 470mm)
420mm f4 (210 + 2.0 TC) (effective 672mm)
588mm f4 (210 + 1.4 + 2.0 TCs) (effective 940mm!)
Now I need to take a moon shot!!
|
|
|
|
12/22/2005 03:32:40 PM · #2 |
can you post shutters for the 588mm and 210mm?
|
|
|
|
12/22/2005 03:50:05 PM · #3 |
|
|
|
12/22/2005 04:06:30 PM · #4 |
| Are you sure it is F4 with the 2x? I would think it would be F5.6. |
|
|
|
12/22/2005 04:52:10 PM · #5 |
Ok, i/m new to TCs and yes, the effetive F stop is not 4...the EXIF and camera read this, so that is i suppose the lens setting of the ap blades.
Lessee if i cna get this right..the fstop is my calculation, the shutter time is accurate.
210mm, f4, 1/1000 sec
294mm, f5.6, 1/640
420mm, f8, 1/320
588mm, ?, 1/125
the first three are easy as we all know a 1.4x costs 1 stop, a 2.0 2 stops. Together, 3 stops? More like 4 stops if going off the shutter speed?
|
|
|
|
12/22/2005 05:25:33 PM · #6 |
Originally posted by Prof_Fate:
the first three are easy as we all know a 1.4x costs 1 stop, a 2.0 2 stops. Together, 3 stops? More like 4 stops if going off the shutter speed? |
It should be 3 stops ( 1/8 th light ) |
|
|
|
12/22/2005 05:35:47 PM · #7 |
So f11 then?
I guess the small discrepency in shutter speed is just a small variation in true Ev then.
It is interesting to note that the true fStop wide open (3 down from 2.8) is f8, well beyond what canon says their non-1D line camera can AF at - and the AF did work.
I did some handheld shots earlier in the day, well, braced shots, and it is hard to hold steady at 940mm. harder still is to get 1/1000 shutter speed, in full daylight even at ISO800 it was hard to get today. Between camera shake and noise, the shots are not DPC quality, but perhaps suitable for the national enquirer!
|
|
|
|
12/22/2005 08:00:09 PM · #8 |
| Your exif data should read the correct setting with the TC's. At least mine do. Are you using the pro version or the standard? That might be it because I think on the Tamron TC's you get the electronic connection and an extra piece of glass with the pro version. |
|
|
|
12/22/2005 09:52:58 PM · #9 |
| Hard to judge on a 640 pixel wide photo, can you post 100% crops? |
|
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 09/21/2025 07:03:20 PM EDT.
