No Sun?...No Problem!

Not a whole lot of sun today, but that is actually a benefit in some cases. Take flowers for instance. Shooting flowers in hard light does not always give the best result. I searched far and wide for a subject photo for this post. Well...not really...I ventured about 6 feet outside the door and found some dandelions growing in a gravel driveway since I didn't trust the weather to be dry for long.

I promised a friend of mine that I would throw some "Photography 101" type lessons into my posts. He just bought a DSLR, and with all the different settings, is a bit overwhelmed. So here you go Allen; let's talk about tradeoffs.

In just about every setting you change when using your camera, there is always a tradeoff. The challenge I ran into today was low-light and windy conditions. Not the best for photographing flowers, but I chose the subject on purpose to show what choices you have to overcome obstacles.

In almost all shooting situations, my personal preference is to set the camera dial in the Aperature Priority position ("Av" on Canon, "A" on Nikon). This allows me to set the depth of field (DOF) that I want, and let the camera set the shutter speed accordingly. What is depth of field you ask? Put simply, it is the window of focus from front to back. If you have a narrow depth of field, very few things are in focus. Take this photo for example. It is shot at a shutter speed of 1/640 sec. and an aperature of f/4.0 and an ISO setting of 100. Also referred to as 1/640 sec @ f/4.0 ISO 100

This is a very narrow depth of field. If you look at the petals on the flower (click on the photo for the full version), the ones in the very front, as well as the ones in the back are all out of focus. There is a very limited amount of this flower that is actually in focus. In this case, the background is usually less distracting and visually pleasing when this far out of focus. In portrait photography, this is the background effect you are looking for.

OK, what setting affects the depth of field? That would be aperature. The more wide open the lens (lower f-stop number), the narrower the DOF. Conversely, stopping down the aperature (higher f-stop number) the wider the DOF.

Remember when I said there are always tradeoffs? In this case, to get a wider (deeper) DOF, you would dial in a higher f-stop. This closes the iris inside the lens to a smaller size in turn letting in less light. In most cases, less light = bigger challenge. Think about it; remember when you wanted to take some photos with your cheap film camera in a dimly lit room without flash. That never worked out very well did it? Here, getting the DOF to be wider is basically cutting down the light source and making the "room" darker. Here is what happens when you stop it all the way down to f/22 which should give you the widest DOF possible.


Wait a second here. Didn't I just say that this would bring more into focus?

This is a blurry mess! Ah...remember the tradeoff? What happened when you took that picture in the dark room? It was a blurry mess wasn't it? Ah...and I bet you forgot that I said it was a windy day didn't you? Well, your super high-tech camera will compensate for that f/22 you just dialed in by slowing your shutter speed all the way down to 1/20th of a second. With these weeds blowing in the wind, there isn't a chance in you-know-where that you are going to maintain focus with your shutter open that long!

Hmmm, now what. That one was shot at 1/20 sec @ f/22 ISO 100. Wait a minute...what's this ISO thing? Ah yes ISO. If you are familiar with film cameras at all, you will remember that when the lighting was dark, you would use a 400 "speed" film. This is basically the same as the ISO setting in your digital camera. Here is a photo taken with the ISO bumped up to 500:


The aperature did not change at all, it's still at f/22, but when I dialed in the ISO to 500 (5x what it was), the camera compensated by making the shutter speed 1/100sec (5x faster). The moving flowers are no longer blurry, and if you notice, the DOF is much wider. The background is no longer as soft, but it is still out of focus. The entire flower is now in focus. Woah! This ISO thing is awesome! Why don't I just dial my ISO up as high as it goes and leave it there? Remember I mentioned the tradeoffs? In this case, just like in the faster film, the tradeoff is "grain". Digitally, it is called "noise". With an entry level DSLR, like the Canon Rebel series, ISO levels above about 400 will start to show noise. These photos were taken with a Canon 5D MkII which has a much broader ISO range, so the noise in the photo above is not really noticable. To give you an example of noise, here is a photo taken at ISO 6400:

If you click on the photo above, and this photo prior, you can zoom in on the shadows and see the effects of the noise. It will appear as randomly colored tiny "spots" that don't seem to belong in the photo. Kind of like a "snowy" analog TV signal. FYI, this photo is 1/1250 sec @ f/22 ISO 6400. Dialing in such a high ISO created a very fast shutter speed.

Well, what did we learn today? That there are way too many settings on your new camera and you are returning it to the store?

NO! You've learned just about everything you need to know to understand why your camera works the way it does. There are really only three settings on the camera that you have control over to overcome obstacles you run into. As I see it, you are trying to maximize your shutter speed to the situation. The slower the shutter speed, the more chance you have of coming up with a blurry shot. The camera will change the shutter speed based upon the aperature. If you need a very wide DOF, you need to stop down the lens which always works against you. If you go too far, your shutter speed suffers, and the photos are blurry. If this is the case, you need to dial in the ISO setting...again, working against you.

So what are the settings that I settled on for my opening shot with the bee in it? I chose to limit my ISO setting to 400 to reduce noise, and I split the difference on the aperature and set it to f/14. The camera then set the shutter to 1/200 sec. which was fast enough to freeze the motion.

If all I've done is confuse you even more, leave a question in the comments section and I'll try to answer it.