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12-13-2013, 01:11 AM   #1
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Push ISO

If I use a 400 ISO film and I changed the ISO on body to 800, what I understood is that it might be underexposed. Seeing that I am most probably going to scan them rather than printing them, it is OK because I can always edit later in post processing, right? Or it won't make a difference later?

12-13-2013, 01:17 AM   #2
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QuoteOriginally posted by azerak Quote
If I use a 400 ISO film and I changed the ISO on body to 800, what I understood is that it might be underexposed. Seeing that I am most probably going to scan them rather than printing them, it is OK because I can always edit later in post processing, right? Or it won't make a difference later?
Why would you voluntarily underexpose? You can oftentimes compensate for errors in exposure during post-processing, but it's always better if you start off with a well-exposed photograph. Plus, film is already pretty tolerant as far as highlights go.

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12-13-2013, 01:43 AM   #3
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Adam, you must not have been a film shooter "back in the day." Push processing a roll of film to get an extra stop was pretty standard procedure when you just had to have that extra speed. I shot a lot of Tri-X and Fujicolor 400 at 800 and even 1600 for theater work, before 800 ASA film became widely available. You could also try it with 'chromes but results were sometimes irregular.

OP - your best course is to ask the lab that does your developing to "push" the processing a stop to 800. Don't wait to try and correct the under-exposure after you scan the film. A professional lab can do this to very close tolerance and get it very close to right on. The films will be a little grainier and more constrasty but that is the name of the game. If you will be developing the film yourself, you should be able to find time/temperature charts for pushing the specific film for 1/2, 1 and sometimes 2 or more stops. The time and temperature are critical. Given a choice, I'd suggest sending film out for push processing.
12-13-2013, 02:41 AM   #4
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Thank you for the feedback.

It was not my intention to underexpose but at times when my shutter speed is too slow, I might want to increase it hence the reason that I increase the ISO on the body. Hopefully the processing by the lab would be done well later. This is my first time using SLR

12-13-2013, 02:58 AM   #5
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By all means expose at 800, but as said above, make sure to let the lab know you want it pushed by a stop.

Pushing means that during the development they'll use a warmer developer bath, and a longer development time.

The result will be correctly exposed negatives, albeit slightly more grain than if exposed at the box speed.



Also, you'll need to push the entire roll, you can't just push half a roll to 800, then the second half use 400. All you'll end up with is one half developed too much/little.
12-13-2013, 03:50 AM   #6
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1stop? Seriously don't worry pushing at all.
12-13-2013, 09:28 AM   #7
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QuoteOriginally posted by hks_kansei Quote
Also, you'll need to push the entire roll, you can't just push half a roll to 800, then the second half use 400. All you'll end up with is one half developed too much/little.
Yeah I was going to mention that as well. It’s all or nothing when pushing/pulling a roll of film, this is not a DSLR.

Phil.
12-13-2013, 09:37 AM   #8
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One stop underexposed on print film won't do much damage, frankly. Print film is quite tolerant. Slide film, on the other hand, has to be shot right on the money or pushed/pulled to the actual exposed ISO.

12-13-2013, 09:50 AM   #9
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QuoteOriginally posted by abmj Quote
Don't wait to try and correct the under-exposure after you scan the film.
+1

Underexposure is just that...less data. Less data = less picture to scan.

You can compensate by using push processing to build density in the negative where the latent image is thin, but the trade-off is more grain and less dynamic range. All push processing does is make scarce data more accessible to the scanner. It does not make something from nothing.


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12-13-2013, 12:16 PM   #10
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Your pics will be fine, you will see a bit extra grain and your midtones maybe muddled.. dpending on which film you used.

if you are going to scan you should be fine
12-13-2013, 07:49 PM   #11
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Thank you for all the comments. I will upload some of my shots once I got them processed
12-15-2013, 06:15 PM   #12
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Just to let you know, with negative films it's always better to overexposed instead of underexposing. You will not be able to recover shadows like you can on DSLR etc... all that info will be lost, forever. All push processing does is increases contrast.

Also you can't just push process 1 photo. You push process all of the photos on the roll.
12-15-2013, 07:27 PM   #13
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QuoteOriginally posted by azerak Quote
If I use a 400 ISO film and I changed the ISO on body to 800, what I understood is that it might be underexposed. Seeing that I am most probably going to scan them rather than printing them, it is OK because I can always edit later in post processing, right? Or it won't make a difference later?
It depends on B&W or color, and for color slide or print. For B&W or E6 processing the best thing to do is increase the processing time to compensate for the under exposure.

Labs can do this for you or if you process your own then you can do it. Color print film ( like C41) is harder to deal with.

I have shot B&W for over 30 years on and off and only rarely shoot at the recommended ISO
12-16-2013, 04:22 AM   #14
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So finally I have got my film processed and scanned. Here are the ones which I changed the ISO to 400.





Any comments?
12-16-2013, 04:46 AM   #15
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QuoteOriginally posted by azerak Quote
So finally I have got my film processed and scanned. Here are the ones which I changed the ISO to 400.
Any comments?
To me they looks good ! you can play a bit with white balance of the first photo ( has a bit too much yellow cast to my taste ) - but otherwise they looks ok to me --manntax
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