Film Speed photography/art/design

[Magruter]

Can someone explain film speed? Just bought BGB's old 35 mm and the wife went out yesterday to bought a pack of 200 and a pack of 800 speed. What are the differences? We are going to vegas today which roll would you have in the camera?

[Bubblegum Bandit]

Short answer. I'd have the 200 in the camera for Vegas. You should have plenty of sunlight to get fine pictures from 200 speed.

 

The way I understand it, someone can correct me if I'm wrong. But it work at the avs game the other day with my digital. If you are in low light situations and want to use a lower aperature your shutter speed will want to be a lot slower....ie, your subject and your camera better be extremely still (on a tripod) or you're gonna get a lot of blur, but by bumping up your film speed your shutter speed can be faster and thus your picture will turn out with less blur shooting hand held.

 

Let me give you the specific situation at the hockey game. I was messing with the camera and in auto mode it told me with iso200 (film speed) and my aperature at 5.6, my shutter speed should have been 1/60. I can't hold my camera still enough to take a shot at that shutter speed without inducing blur, I'm too shakey..lol. So I bump up the iso to 400 and again check what the auto on my camera says, with the same aperature I can shoot with a shutter speed of 1/200, which is fine for me for handheld.

 

The way this makes me think about it is like the difference between a 5200(200 speed) rpm hard drive and a 7200(400 speed) rpm hd. The information will be writen to the film faster which is good. However, with film, the faster you write the info the more loss (grain) you can get into the picture. The more light you have, the less loss you will get.

 

Thus the fun of photography.

 

Anybody add to that, or correct? That's the way I understand it so far.

[appalachian_fox]

That's pretty much how I understand it, BGB, of course my understanding is pretty basic. We use a lot of large-format film when we fly aerial photography, and I tried my hand at amateur photography for a little while, so again my understanding is basic enough to get by using cameras but I think you covered the important stuff for a last-second class.

[Scourge]

I find the eastiest way to understand that stuff is to know whats going on.

First, the general. Iso is how sensitive the film (or digital sensor) is to light.

 

When you take a pic there are three main factors to affect the outcome. Your shutter speed, apeture, and Iso.

 

Shutter speed: It's how long the camera lets the film(sensor) see light. The longer the shutter speed, the more light you get. The general rule of thumb for shutter speed is no longer(slower) then 1/focal length. For example, if you are shooting with a 50mm lens, don't go lower the 1/50th of a second.(This will, of course, differ greatly from person to person depending on how steady you are). Personally, i never go lower then 1/60th while shooting freehand. This formula is a little more important when using longer telephoto lenses. If you are using a 200mm lens any shake is going to be more obvious since everything is magnified, so you would want to shoot at 1/200th of a second or faster. Also, if you are shooting an action scene you will want a faster shutter speed to "freeze" the action. Too slow a shutter speed and eveything will blur.

 

Apeture: The apeture, or F-stop, is the size of the hole the light comes through in the lens. Bigger hole = more light. Apeture size is also measued as a fraction, F2.8 is actually 1/2.8. So F5.6 is a smaller hole then F2.8. It also affects what is called the depth of field. Basically, DOF(depth of field) is how much of the picture is in focus at once. Example: You focus on a person's face 2 feet in front of you. With a wide apeture, say 2.8, you may not be able you get the whole face in focus at once. The eyes are in focus, but the nose ia a little fuzzy. This would be because the depth of field is only a few inches(so anything more then a couple inches in front of, or behind the focus point will be out of focus). If you were to close the apeture a bit, down to F8 or so, suddenly the whole face can be in focus at once because the DOF would increase from a few inches to 6 or maybe 8. So you have to decide ... do you need DOF, or more light?

 

ISO: Like I said, that is how sensitive the film(sensor) is to light. The higher the number (800) the more sensitive the film. The common speeds range from 100-1600 ISO. The sacrifice for having a more sensitive film is a loss of quality(although sometimes that may be the effect you're looking for). The guality loss manifests itself in the form of "grain". Just like it's name, think of rice. Best example, take a point and shoot digital camera(something nice and compact) set it on a table in a dimly lit room in full auto mode(but turn the flash off) and take a picture(I say set it on the table so you don't get any blur). You'll see how the picture quality is somewhat lackluster(unless you have a really really good camera, lol). Grain is most evident in darker parts of the picture.

So when looking at ISO, generally, you want the lowest number and least sensitive you can use because it will give the best pictures.

 

 

Now, all three of these things combine to balance the lighting in your picture. When I shoot, I choose what F-stop I want to use first, then I start at 100 iso. If the shutter speed is too low, I go up to 200, 400 and so on. Now obviously that's a little hard to do on a 35mm(I usually shoot digital) so you will have to anticipate what conditionss you will be in. For vegas outside daytime shooting, 100 or 200 iso will be great. 400 if you're shooting some really fast action. If you are going to be indoors, you'll want 400 or 800, although depending on lighting that may still not be enough(you'd still be able to take a pic, you'd just have to get so slow on the shutter speed that it will blur unless you have something to hold the camera, ei. tripod).

 

Lol .... that turned into a really long post .... ah well. I hope this is understandable. I did repeat some of the stuff BGB said ....

 

HTH

-George

[appalachian_fox]

Good info! Thanks! Long post is alright, because it covered the nuts and bolts in English so we can all understand it.