Is there any database online of legacy lens T-stop ratings?

Discussion in '35mm Cameras and Accessories' started by Modern Minoltian, Feb 6, 2013.

  1. Modern Minoltian

    Modern Minoltian Member

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    Or is there perhaps a way I can determine it on my own?
    I know it's not usually that different from an F-stop, from what I understand, I'm mostly just curious.
     
  2. StoneNYC

    StoneNYC Subscriber

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    T stop? I've never seen that and I have some cameras from the 1910's how old is that "system"?


    ~Stone

    Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk
     
  3. StoneNYC

    StoneNYC Subscriber

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    Are you sure you don't mean like the B/T/I settings on an old lens? T means time, which is like Bulb except it will stay open after releases and only close after you click the trigger a second time, often used for very long exposures.


    ~Stone

    Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk
     
  4. MattKing

    MattKing Subscriber

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    T-stops are used primarily for motion picture lenses - they provide a more exact measurement of the light transmission of a lens then the slightly more theoretical f-stops.

    The difference is usually small, and generally only relevant in the exacting circumstances of motion picture work.
     
  5. Modern Minoltian

    Modern Minoltian Member

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    Exactly. It's the standard measurement used for cinema lenses, it's the F-stop corrected for absorbance and reflectance. It is usually very close to the F-stop, I was just curious as to whether some manufacturers' lenses might be more affected by absorbance and reflectance than others. But I guess guess if the T-stop was never given by the manufacturer, it'd be pretty hard to figure out.
     
  6. StoneNYC

    StoneNYC Subscriber

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    Oh well don't I feel like a fool, especially because I work in the movie industry haha (but not on the camera crew side..yet).


    ~Stone

    Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk
     
  7. Ian Grant

    Ian Grant Subscriber

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    It's also worth bearing in mind that the transmission of lenses improved very significantly with the advent of coatings in 1938 although it was after WWII when coating s became universal on all quality lenses.

    The first coated lenses from Zeiss have a red "T" designation for Transparent, earliest I've seen was a 1938 CJZ 15cm f4.5 Tessar, I have an early 1950's version and the coatings are excellent althogh a touch blue for colour work.

    Before coating was commom many photographers processed to higher negative contrasts to help overcome slight lens flare, by the early 1960's this had changed and the ASA/BS testing of films was revised resulting in nominal film speeds being doubled (Tri-X went from 200 ASA to 400ASA).

    Ian
     
  8. jochen

    jochen Member

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    before WW II the old f-stop system was often used: 2.2 / 3.2 / 4.5 / 6.3 / 9 / 12.5 / 18
     
  9. Mr Bill

    Mr Bill Member

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    I don't have any lens-specific info for you, but do have an old standard, Method for Determining Aperture Calibration of Motion-Picture Lenses. It's USA Standard PH22.90-1964 (reaffirmed in 1969). This was the standard for determining both f-stops and t-stops back in the day.

    It's too tedious to describe, but if you look up Appendix II at the following link, it looks like the same basic info: http://www.archive.org/stream/journalofsociety53socirich/journalofsociety53socirich_djvu.txt

    Even if you can dredge through it, my guess is that you'll decide you can live without t-stops.
     
  10. Ian Grant

    Ian Grant Subscriber

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    Not by many manufacturers, my 1913 CZJ 165mm f6.3 Tessar has the tradional 3, 5.6, 8, 11, 16, 22, 32, in fact of all my pre-WWII German lenses (over 16) only my Summar has the other syste.

    Ian
     
  11. Chan Tran

    Chan Tran Member

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    I don't know of any chart but you can measure it yourself.
     
  12. Les Sarile

    Les Sarile Member

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    The old lens reviews listed the T-number of the lenses. In this page a Rokkor 50mm f1.4 with a T-number 1.53, 28mm f2.0 with a T-number 2.25 and a 135mm f2.8 with a T-number 3.11. In these examples it doesn't seem significantly off.

    [​IMG]
     
  13. Dan Fromm

    Dan Fromm Member

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    Les, you have the small child's concept of old.
     
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  15. Dan Fromm

    Dan Fromm Member

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    Usually small? Perhaps, but not always. Consider the 8-64/1.9 Angenieux 8x8B as was supplied with the Beaulieu 4008ZM. It t stops around t/3.3. Mine taught me to check all of my cine camera zooms for transmission, against the evil day when the camera's on-board meter failed.
     
  16. dynachrome

    dynachrome Member

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    This brings back the old discussion of full aperture metering vs. stop down metering. Some people thought stop down metering was more accurate because it measured the light coming through the lens rather than the setting based on the f/stop set on the lens. Full aperture metering has been around for a long time. Some cameras had it earlier than others. The Minolta SRT-101 had it in 1966. The Konica Autoreflex T had it in 1968. The Canon F-1 and FTb cameras had it in 1971. Pentax did not have it until the ES of 1971. Before the Micro Nikkor P Nikon made the 55/3.5 Micro Nikkor Auto which had a mechanical exposure compensation in the close-up range. This made things easier for someone who was using a separate meter and wanted to get proper exposure up close. To use it with a camera with TTL metering you would need to stop down to meter. If you are using a camera like the Minolta X-700 and are set to aperture priority, the camera will read the actual amount of light coming through the lens and will not depend only on the f/stop the lens is set at. Your finder may show a shutter speed of 1/250 but the actual shutter speed at the moment of exposure may be faster or slower than that. This would cancel out any minor differences between the marked f/stop and the actual T stop.
     
  17. StoneNYC

    StoneNYC Subscriber

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    Perhaps you're just ancient... The fact it's written on paper in a magazine means its old... Hehe


    ~Stone

    Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk
     
  18. E. von Hoegh

    E. von Hoegh Member

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    No, no, no. The fact that it's in a magazine means it's not old. If it was on a parchment scroll, it'd be old. :wink:

    Let's keep some perspective here.
     
  19. Prof_Pixel

    Prof_Pixel Member

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    I've seen T stops used with view cameras when large extensions were used (close-ups).
     
  20. StoneNYC

    StoneNYC Subscriber

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    In this world older than 10 years is old... I was driving these kids in a car that was 7 years old and they said "wow this car is so old look at all the knobs and buttons!" Because their patents owned a new car with touch panel displays etc.

    It's a new generation and everything is fast and obsolete :smile: or rather :sad:


    ~Stone

    Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk
     
  21. E. von Hoegh

    E. von Hoegh Member

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    Yep. Their loss, my gain.:smile:
     
  22. AgX

    AgX Member

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    This is a difference of 1 1/2 stops!!
     
  23. Ian Grant

    Ian Grant Subscriber

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    Well some of those early Zoom lenses on cine cameras had rather a lot of elements so even with coating there was still quite a significant loss of light, prior to coatins they weren't practical at all.

    Ian
     
  24. AgX

    AgX Member

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    The Angenieux 10-150mm f2 had a loss of 1/4 stop.
     
  25. Someonenameddavid

    Someonenameddavid Member

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    I Have a 50mm T2.2 Taylor Taylor Hobson which you can have for $1500: it's attached to a Bell and Howell Foton in excellent working order.

    David. I use f stops, the T stop thing in still photography is hype.
     
  26. StoneNYC

    StoneNYC Subscriber

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    This makes me wonder about my Canon 70-200 2.8 USM IS Mark II as its a beast and I have hear that though it is a 2.8 the amount of glass cuts down on light throughput. Hmmm... Wonder what the T stop is on that baby...


    ~Stone

    Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk