Ektachrome 64T

[T-Scan]

How does that work out?

1/3 from 25asa is 32asa, 2/3= 40asa, 1 stop= 50asa

[Angus]

(a speed difference of 24ASA)

This statement has no meaning.

ASA is not a unit like ounces or grams or miles per hour.

It is meaningless to talk about a difference of "24 ASA" without stating your starting point and if you are under or over exposing...and even then nobody would ever say "I am taking 100 ASA film and over exposing by 24 ASA"...they'd say "I am taking 100 ASA film and over exposing by almost a quarter of a stop"

Remember its a logarythmic scale.

Lets start with a 24 ASA film, to use your example.

Under expose one stop....48 ASA....we have added "24 ASA"

under expose one more stop....the number *doubles" again to 96 ASA...to achieve the same effect again, one f-stop...we have added "48" ASA....next time we would add "96 ASA" and so on.

This is why we talk of fractions of a stop + or -.

The difference between K25 and Velvia 50 is "25ASA". In this case it is one whole f-stop.

The difference between Superia 1600 and t-max 3200 is "1600ASA"........or one whole f-stop as the starting on the log scale is different.

My daddy taught me that when I were a wee lad of 6

[tlatosmd]

I prefer Einstein's physics, they're so much simpler.

[S8 Booster]

are you sure about that? ;-)

ASA 25 -- 0
32
40
50 -- +1 stop
64
80
100 -- +2 stops
125
160
200 -- +3 stops
250
320
400 -- +4 stops

[mattias]

1.25 is the only number you have to remember. it's the factor of 1/3 stop. keep multiplying.

/matt

[Mogzy]

(a speed difference of 24ASA)

This statement has no meaning.

ASA is not a unit like ounces or grams or miles per hour.

It is meaningless to talk about a difference of "24 ASA" without stating your starting point and if you are under or over exposing...and even then nobody would ever say "I am taking 100 ASA film and over exposing by 24 ASA"...they'd say "I am taking 100 ASA film and over exposing by almost a quarter of a stop"

Remember its a logarythmic scale.

Lets start with a 24 ASA film, to use your example.

Under expose one stop....48 ASA....we have added "24 ASA"

under expose one more stop....the number *doubles" again to 96 ASA...to achieve the same effect again, one f-stop...we have added "48" ASA....next time we would add "96 ASA" and so on.

This is why we talk of fractions of a stop + or -.

The difference between K25 and Velvia 50 is "25ASA". In this case it is one whole f-stop.

The difference between Superia 1600 and t-max 3200 is "1600ASA"........or one whole f-stop as the starting on the log scale is different.

My daddy taught me that when I were a wee lad of 6

Thanks for that. I didn't understand it- now I do, 14 years too late by the looks of it!

[cubdukat]

just did some "tests" with the e64t at 0 +1/3 -1/3 and found it rather forgiving. here are some totally diy transferred images which of course is way off a professional transfer reference but may give an indication. proper transfer planned later. shot with 85b filter.

all images can be magnified by a click.

-1/3


00


+1/3


just add the e125 for a sort of reference. not satisfied with the e6 processing. gone less "sharp". exposed t 80.



for reference of transfer tech only - exactly the same as above - plusx at 00.

Looks pretty good, but what I'd like to know is how forgiving it is on the extreme end.

I though that someone had shown some tests in which they took it to a full stop in both directions and still got a usable image--just barely, but that's certainly more than you'd expect out of a reversal film.

Sadly, my 514XL-S is one of the cams that seriously underexposes E64T (supposedly 1 1/3 stop) unless you play around with the EE lock control.

[Angus]

I prefer Einstein's physics, they're so much simpler.

Took me another 10 years to grasp special relativity.

and a further 6 years after that to grasp general relativity.

Bends your head far more than LSD...

[John_Pytlak]

1.25 is the only number you have to remember. it's the factor of 1/3 stop. keep multiplying.

/matt

1.25 is close, but no cigar.

1/3 stop Exposure Index increments are actually the
cube root of 2 = 2^(1/3) = 1.25992105 apart.

Similarly, 1/2 stop Exposure increments are the
square root of 2 = 2^(1/2) = 1.414213562...apart.

Full stop increments are a factor of 2 apart.

The recognized nominal film exposure indices are 1/3 stop increments:

20, 25, 32, 40, 50, 64, 80, 100, 125, 160, 200, 250, 320, 400, 500, 640, 800, 1000

[S8 Booster]

although the ISO/ASA scales are sort of straight forward i would preffer the "reel" stuff ;-)

[aj]

I though that someone had shown some tests in which they took it to a full stop in both directions and still got a usable image--just barely, but that's certainly more than you'd expect out of a reversal film.

I would say there is indeed not much play in reversal film. And only somewhat more in negative.

But this brings to mind that in another thread about telecine people want to bring on screen some 10 stops of exposure range. Makes one wonder where these come from

[S8 Booster]

all images can be magnified by a click.

-1/3


00


+1/3


just add the e125 for a sort of reference. not satisfied with the e6 processing. gone less "sharp". exposed t 80.



for reference of transfer tech only - exactly the same as above - plusx at 00.



Looks pretty good, but what I'd like to know is how forgiving it is on the extreme end.

I though that someone had shown some tests in which they took it to a full stop in both directions and still got a usable image--just barely, but that's certainly more than you'd expect out of a reversal film.

Sadly, my 514XL-S is one of the cams that seriously underexposes E64T (supposedly 1 1/3 stop) unless you play around with the EE lock control.

ill try to help you put a bit on the way.

here are some iomages from the same film transferred at the same tim n method no changes in video transfer settings.

this time the built in plain 85 filter is used.

first image is exposed at 00 - normal exposure. the next below is shot at -2/3


"normal"


not completely sure if i shot this at -3/3 or -2/3 but in reality it is really grainy and underexposed.



it appears that the 64 works truly best in all parameters with the 85b filter over the plain 85 built in. its like a totally different film, as if the ei/sensitivity is kind of different with the 2 different filters.

we know that the k40 was iso 32 in tungsten 3200 and 40 with photo lamp 3400. possibly an alalog situation with the 64t, thus filters charge in?

my impression /T winola DuNots.

[T-Scan]

it appears that the 64 works truly best in all parameters with the 85b filter over the plain 85 built in. its like a totally different film, as if the ei/sensitivity is kind of different with the 2 different filters.

Totally, Your 85 pics are cold with a bluish hugh. I've only taken a few shots with an 85, and they show more grain from what i've seen. The 85B gives me the richest colors I've ever had from an s8 color reversal.

[John_Pytlak]

Color negative films have MUCH more exposure latitude than reversal films that are designed for direct projection.

For SMPTE members, here is an article in the April 2006 SMPTE Journal that has a very good discussion of film latitude:

http://www.electronicipc.com/journalez/ ... =&cftoken=

[S8 Booster]

I though that someone had shown some tests in which they took it to a full stop in both directions and still got a usable image--just barely, but that's certainly more than you'd expect out of a reversal film.

I would say there is indeed not much play in reversal film. And only somewhat more in negative.

But this brings to mind that in another thread about telecine people want to bring on screen some 10 stops of exposure range. Makes one wonder where these come from

easily does -4 to +4.2 it seems...

v2 500t

Example of Original Negative Exposure Data
KODAK VISION2 500T Color Negative Film 5218 / 7218
Download an Adobe AcrobatTM version of this file for printing. ( 59K)

Lens: 32 mm ZEISS Ultra Prime Lens
Filter: None
Aperture: T 2.8
Incident Light Levels
(Tungsten 2950K):
Key = T 2.8 (20 fc)
Fill = T 1.3 (4 fc)
Backlight = T 5.0 (64 fc)

Stop notations listed on the photo are reflected-light readings.

Note: There is a small amount of atmospheric smoke in the scene.

200t