Pushing Provia 100F

Those of you who have followed this blog know that I am primarily a slide film shooter.  Lately I’ve been shooting mostly Fujichrome Provia 100F.  Ordinarily I shoot film at box speed.  Well with my son’s birthday coming up, I decided I wanted to shoot with faster film, so stopped by my current favorite local camera store, Creve Coeur Camera (in Springfield, IL).  Okay, CCC is an hour away, but I work in Springfield so it was no big deal to swing by there and see if they had any Provia 400X.  Sadly they did not, nor did any of their stores, but said they could order it.  Time was getting short for me, and I didn’t want to order it from them (I could have had it from B&H in 2 days, but it would’ve been too late for the birthday party).  They would’ve happily sold me Provia 100F, but I already had several rolls of that in the fridge at home so I declined.

Slide film has next to zero latitude in standard processing.  What you can do, though, is process it with a non-standard time, which gives you some flexibility to shoot the film at an ISO that is different from the ISO shown on the box.  If you shoot with a higher ISO, you need the film to spend more time in the developer (this is called push processing).  If you shoot with a lower ISO, you need the film to spend less time in the developer (this is called pull processing).  Fuji says you can pull Provia 100F 1/2 stop, or push it 2 stops.

I’d never pushed film before, so I decided that now would be a good time to try it (yes, I know, bad idea because I was going to be trying it for the first time at my son’s birthday party).  Enter the Internet (sadly I didn’t save any of the links so I cannot cite them here – just google “Provia 100F pushed to 400.”  I found quite a bit of info about pushing Provia 400X to 1600, not so much pushing 100F to 400.  Some folks said that if you do a 2 stop push, you should rate the film at ISO 320 instead of 400, and that the contrast would be increased slightly and you might lose detail in the darkest shadows.  Also there would be more grain (Provia 100F at box speed is almost grainless).

Well, I went for it.  I grabbed the film from the fridge, wrote “Push 2 stops” on the cassette with a sharpie, and loaded it into the camera, remembering to override the ISO to 320 instead of 100.  Got the film back earlier this week and projected it on the wall about an hour ago.  Pictures came out great.  I didn’t see any more grain at ISO 320 than I would’ve at ISO 100.  The contrast is a bit higher because I had the lab push 2 stops.  Highlights were not blown, and shadows still retain a good amount of detail.  Skin tones and color were also good, but with a slight shift towards red in some of the skin tones.Skin tones show a slight red cast.  Otherwise the color is good.
Flesh tones shifted slightly to the red in this photo.

The pond in late afternoon/early evening from the stone railroad bridge

The pond in late afternoon/early evening from the stone railroad bridge

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I can’t wait to see how this looks in B&W infrared in the summertime, but that’s a topic for another time.

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My Return to Shooting Film

When I was a child and well into my adulthood, still photography was all done on film.  I quit shooting film cold turkey in 2001 when we got our first digital camera.  I liked the immediacy of seeing the picture as soon as I took it, and knew immediately whether or not it turned out okay.  You don’t get that with film.

As a child, and later a college student, I shot slide film and projected it.  First, because by projecting slides, you can see your images in whatever size you want, and second because even though the slide film was more expensive than film for prints, it was cheaper to process, which was important to me because as a boy (and later a college student), keeping costs down meant I could actually afford to have this as a hobby.

Fast forward to early 2011.  I had been shooting digital only for ten years.  Had never gotten the slide projector out in all that time.  I’d just purchased a scanner with the intent of digitizing all the pictures I’d shot years before, and was going through the slides in a drawer looking for the ones I’d taken on a trip to Yellowstone.

I need to back up for a sec.  My son is a big Penguins of Madagascar fan.  In one of the episodes, the penguins are having a slide show to prepare for a mission.  This was my son’s only exposure to slides up to this point.  I needed to tell you that so you will understand his reaction.  Returning to early 2011 now…

My son walks into my bedroom where I am looking for the slides of Yellowstone, and his eyes got as big as dinner plates.  He said “Whoa, Dad, what are these?”  I explained what they were and he said “Can we look at some?”  I promised that if the projector I had stored in the garage still worked, that we would look at some that night after it got dark.

The projector hadn’t been used in 12 years and guess what – it still worked!  My nephew was over that night and we had a slide show.  My nephew said they looked better than digital, and it got me thinking that I needed to have slides to project.  After doing some research, I discovered that the least expensive way to get slides was to simply shoot slide film rather than shoot digital and then put the files through a film recorder.  And that’s how I returned to shooting slide film and projecting the results, just like when I was a boy.

Strange Number Sequence in Photography

In my last photography post, I shared three sets of numbers: Film (sensor) speed, Shutter Speed, and Aperture (f-stop).  The sensor speeds and shutter speeds made sense; each one was roughly double or half the preceding number.  The aperture series of numbers, however, was rather odd.  If you’d like to know why that set of numbers is so odd-looking compared to the other two sets of numbers, read on, this post is for you!

The numbers in the aperture series represent the ratio of the focal length of the lens to the diameter of the aperture.  That’s why it’s called an f/number, and why in my last article you saw me refer to an aperture as f/11 instead of f11.  By using a ratio, photographers avoid having to memorize a different sequence of numbers for each focal length lens they own.  Imagine what would you have to do for a zoom lens!  Thus f/8 on a 100mm lens lets in the same amount of light as f/8 on a 28mm lens which lets in the same amount of light as f/8 on a 500mm lens.

But why aren’t the numbers doubling or halving as you step through the sequence?  Because the amount of light that passes through a given aperture is dependent on the area, not the diameter of the opening.  In High School Geometry class, we learn that the area of a circle is equal to pi times the square of the radius.  So for a 100 mm lens, f/2 would have a diameter of 50mm.  The area of this aperture on this lens is 3.14 x 25 x 25 is about 2000 square mm.  The next number in the sequence, f/2.8, would have a diameter of approximately 35.714 mm.  3.14 x 17.85 x 17.85 is about 1000 square mm.

Instead of memorizing the whole sequence, there’s really only two numbers you have to remember: 1.4 and 2.  Double 1.4 and 2 and you get the following two sequences:

  • 1.4, 2.8, 5.6, 11, 22
  • 2, 4, 8, 16, 32

Merge the two series together in ascending order and you get the whole series:
1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32.

Math and Photography

Here are some numbers for you:

  • Sensitivity: ISO 50, 100, 200, 400, 800, 1600, …
  • f/stop (size of lens opening): 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, …
  • Shutter speeds (exposure times): 1, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000, …

The first set of numbers is a range of sensor sensitivity (or film speeds, if you prefer). Each succeeding number is double the previous number, which means that half the light is needed for each step right that you go on the scale. The second set of numbers is the sequence of f/stops commonly found on camera lenses. Each succeeding number lets in half the light per unit time of the previous number. Thus f/4 lets in ½ the light of f/2.8, and ¼ the light of f/2. The third set of numbers is the set of numbers used to indicate shutter speed on most cameras. Each succeeding number exposes your sensor, whether it’s CCD, CMOS, or film, for half the time of the previous number. That third sequence should probably be written 1s, ½, ¼, 1/8, 1/15, 1/30, 1/60, 1/125, and so on, but most camera manufacturers dispense with the “1/” since it’s implied.

What does this have to do with photography? Actually, a lot. For a given light level (let’s say it’s a sunny spring or summer day), in the sun, there is an amount of light that is needed to produce a correctly exposed image. The amount of light that is needed is inversely proportional to your sensor’s sensitivity. That is, the amount of light needed goes down as your sensor’s sensitivity goes up.

There are several combinations of shutter speed and f/stop that will let in the same amount of light. For our scenario of a sunny day, with your subject (let’s say it’s your dog) in full sun, and a sensor sensitivity of ISO 200, the correct exposure would be 1/250 second at f/16. But you could also get a correct exposure at 1/125 second at f/22, or 1/500 second at f/11. Why would you want to vary your settings? Because maybe your dog is running across the yard, so you want a higher shutter speed to freeze his motion (or a lower shutter speed to show motion with blur). As you go to the right on the f/stop scale above, for each position in the sequence you go right, you must go left one position in the shutter speed sequence to get an equivalent exposure. Likewise, if you go right one position in the shutter speed sequence, you must go left one position in the f/stop sequence to get an equivalent exposure. It’s all about the math. In most cases, your camera’s built-in meter will figure this out for you automatically, but it can also be useful to take control of some of the parameters yourself!