Friday, March 06, 2009

F-Stop Friday: The Big Boy F-Stops

Good morning everybody,
I want to start off today by giving my blogging buddy, Syl Arena, a great big THANK YOU for all the good press supporting my upcoming Digital WakeUp Call tour. If you recall, I announced my"Bloggers Unite" contest [link] on Monday and Syl was one of the first to respond. I have to tell you, he put together a "first class" post about the tour and has his "Exciting Lighting" contest cooking too. Syl has done it right - go check it out. If you bloggin' guys and girls want to get in on the action, check out my Monday post, check out to see how to set it up, and send me an email and if you qualify, we will get you set up.

Now who is this Syl Arena you ask? He's the guy who hooked up 12 Canon 580EX2 strobes via Radio Poppers so he could take Digital Mastery guru, Ben Willmore's picture [link]. But wait, there's more - Syl was also "Guest Blogger" for NAPP buddy, Scott Kelby recently - here is the link to his post.

The Big Boy F-Stops
And welcome to another episode of F-Stop Friday. In today's post I want to talk about the big boy at stops - F1.2, F1.4, and their little brother F2.0. Occasionally when I'm shooting a wedding, particularly in the low light situation, I have my second camera strapped over my shoulder and fitted with my 50 mm F1.4 lens. The ISO set to 1600 - 3200 on my new Canon 5D Mark II and "I'm loaded for bear."

Hit The "Read More..." link below for the rest of the story.

This is my candid camera -- the camera I use to unobtrusively photograph the more private candid images of the wedding day. That would include the girls getting ready, the guys getting ready, available light images at the back of the church just before the bride and her dad walk down the aisle, tender expressions with tears, etc. These are moments where I really don't want the flash to intrude into the scene.

But here's the deal though . When using your lens at such a wide aperture, the depth of field is reduced substantially. Now this can be a good thing and this can be a bad thing. It's a good thing because it separates the subject from the background very effectively. The bad thing is the shallow depth of focus. Let's look at the depth of field with a 50mm F1.4 lens at say 10 feet - you have a whopping 7 inches depth of field! Many times I would be using this lens at even a closer working distance say 3 to 5 feet, to pick up some details of the wedding day. The depth of field at 3 feet is only 3/4 of an inch and at 5 feet increases to 2 inches. You better have your focus nailed here.

Our focus needs to be "dead on". That means that any slight change of our distance or the subject's distance to the camera will put the subject quickly out of focus with only a slight shift in position. The solution to this is to put your camera on AI Servo focus or "focus tracking."
In AI Servo focus mode, the camera will follow the focus and you can be assured of a more consistent sharp focus on your subject when taking these kinds of photographs.

I generally use the center spot for focusing in these kinds of situations. When photographing people, be sure that you focus on the eyes as that's what you want to be assured is in sharp focus in your image. Using this very shallow depth of field can be a very creative tool in our photography. But, it can also be a pain in the neck. That being said - I challenge you to be extra careful in selecting your focus spot when using the wider apertures.

When using my 70-200mm F2.8 IS lens I occasionally shoot it at F2.8 but not very often. I prefer shooting at F4.0 or F3.5. I always feel I have a bit more of a safety margin in the focus at that point. The same is true when I'm shooting my 50 mm F1.4 lens. I prefer shooting at F2 because of the added focus safety margin - a whopping 3/4 inch at 5 feet - at that particular aperture.

So the bottom line is this - I rarely use my lenses wide open just simple because of the shallow focus situation and I prefer to use a sweeter (sharper) center part of the lens.

Z-Note: When using a camera with an APS size sensor - like the Canon 50D, you are always using the sharpest part of the lens' image circle.

Whether you plan to shoot wide open or close down half a stop, I still suggest using AI Servo focus mode so that your camera will track focus on the subject and you'll be assured of a much sharper image.

Also remember that even though we can shoot at these very wide apertures to capture the faintest amount of light, that still doesn't necessarily mean that we are shooting at fast shutter speeds to stop the action. Sure we may have a nice tight focus on the subject but the action may give us motion blur that degrades the image. That's why I really like the new high ISO cameras and have no compunction about photographing at ISO 6400 on the new Canon 5D Mark II. You Nikon shooters have the same ISO range to work with too. Noise levels are not terrible even at this high ISO and with the noise reduction software NIK Define 2.0, we really have an easy solution to any noise that might creep through.

Now speaking of low light situations, another place I like using these wide-open apertures and high ISOs is at the wedding reception. I like capturing a different kind of reception photograph - available light candid photographs in the dark surrounds of the reception hall. It just brings a different "flavor" of imagery to our wedding photography. It's a kind of imagery that our clients are usually not used to seeing. It's one more kind of image that just helps differentiate us from the rest of the shooters in our area.

Remember it's always about differentiating yourself from the competition that makes you easier to be noticed by your prospective clients. Remember too, that you can charge a lot more for "differences" and you can for "samenesses." Anyway, it's time to open up and enjoy the shoot!

Hey gang that's it for me today. We have a busy day at the studio and I promised my book publisher I'd get this book wrapped in the next few days. So, everybody have a great weekend and I'll see on the flip side. Adios, -- David

1 comment:

  1. Thanks for the insight David.
    Occasionally I shoot at 1.4 and ISO 3400+. Recently shot 80+ of a wedding with no flash. Only the high ISO cameras make that possible (We use the 5D MK II). We would like to see some insight on work flow for handling the noise at the 6400 level. What is your recipe? Thanks for the share!