ISO question

[zio]

when somebody mentions their film is TMax 400 but it's pushed to 1600 what does that mean? I think i saw somebody mention it on the high contrast section of the photo themes. I know about TMax 400, but my question is...what is pushing it to a different ISO do? and how do you do it?

 

[Kent Frost]

That's a 2 stop push. If I'm not mistaken, isn't that a pretty big push? I've never gone more than a stop.

Pushing 400 film means that while using 400ISO film, you set your camera for 1600 and have the lab develop for 1600.

One trick I used to use was to use 400, but to set the camera for 340 and have the lab process as normal. I always found that to add a bit of contrast.

 

[jack]

hi zio
like your signature btw
i want to do some of this push biznis too.
i think i shot a 200 color film recently and the
ISO computer on my camera was set on 400.
the prints had deep blue skies (no 81B on the lens)
and were lightened but not blown. contrasty and
definately grainy. this was done by mistake. with a
planned idea it could look good. load your tmax and
set the ISO on the camera at 1600 and treat it as 1600.

i'm lazy with my camera. i havent even tried the +1 +2
1/2 & 1/4 light compensator on it yet ( for backlit, spotlit situations).

photos can be pushed during development also, of course.

 

[havoc]

Your not "treating" it like 1600 iso film except from the actual taking of the picture. Pushing the film increasing film speed yes, but the most important part is increasing development time. If you take a roll of 400 Tmax, and push it to 1600, then develop normally you will get nothing but black negatives, because the film itself wasn't exposed long enough to light at normal development times to show up on the neg. However if you over develop, say 20% longer, then the developer has more time to eat away the unexposed silver and creates a high contrast version of the picture you took. The more you push, the longer you have to develop, and the more detail you lose.
Many people choose to push film rather then carry different speeds with them, and they decide to live with the quality loss associated with it.
Comsumer color films are not very pushable usually, Kodak films can usually be pushed only one stop, i.e. 200 to 400iso, and so on. Pro B&W films can be pushed up to 6400iso sometimes Tri-x 400 for example is very pushable, and i think looks better when pushed then when exposed normally.
Just remember though, B&W pro film require special development that Walmart photo shops and the like usually don't carry. Sometimes they are stupid and try to dev. them in color chems, that makes for an interesting roll. If you don't do it yourself, you have to take it to a pro shop that can dev. them for you, and make sure you tell them exactly what you did to the film so they can compensate for your push.

 

[ksmattfish]

If you take a roll of 400 Tmax, and push it to 1600, then develop normally you will get nothing but black negatives, because the film itself wasn't exposed long enough to light at normal development times to show up on the neg.

Of course what Havoc meant is that you'd get clear negatives. If your negs are black they are way overexposed.

Underexposed slides and prints made from under exposed negs, which are positives, would be black.

Sorry to nitpick, Hav, you know how I am.

 

[havoc]

LOL, well your right, so we will let it go this time LOL

 

[zio]

i appreciate the help...i'm goign to go and shoot some waterfall pics...maybe i'll try it out.


cheers,
sean