Relation between lens diameter and f-stop. (From Panasonic.com)
In the last lesson we performed an experiment to focus the light of a candle through a lens. We also learned that to determine the focal length of the system, we move the focusing screen forward and backward until the image of the flame is in focus. Let’s consider that candle/lens system for a moment. What do you think would happen if we replaced the lens with one that is twice the diameter with the same focal length? Would the image be twice as bright? Image twice as large? If you guessed the larger lens would make the image brighter, you would be correct. The larger lens has more area to collect light, which actually equates to an image more then twice the brightness at a ratio equal to πr² where r equals the radius of the lens. The image would, however, be no larger since the focal length of the lens is that same. Continue Reading “Photography Snapshot: The Power of Lenses” »
From Hubblesite.org. Credit: NASA, ESA, and A. Feild (STScI)
In my previous Photography Snapshot, I discussed the importance of light and how it bounces to create images. We discovered that the most primitive form of photography was the camera obscura, which works by excluding all light rays that don’t create an image. While this method does create an image, that image is usually very dim because so few light rays create the image. In this Snapshot we will discuss the difference between reflection and refraction, how a lens focuses light and how a lens’ focal length will impact an image.
A pencil looks bent, because the light bouncing off the part in the water is moving slower than the part through the air.
Light is a form of energy, and while it can bounce and be conserved, it can also bend by being slowed down. I bet you are thinking to yourself, “But light travels at a constant speed!” Light only travels at a constant speed in the perfect vacuum of space where it doesn’t encounter any opposing forces. You can slow light down by having it pass through materials like air or water. According to Snell’s Law, the degree of refraction depends on the ratio of the two materials’ different refractive indices. Most materials have a refractive index greater than one, which means that as light enters the material from air, the angle of the ray in the material will be more nearly “normal” (perpendicular) to the surface than it was before it entered.
Give it a shot: shine a flashlight through a jar of water. Does the beam look straight? Put a pencil in a dish of water; it looks like it bends where the water and air meet.
I had never heard of this website, despite the fact that they’ve been around for four years now. It wasn’t until I was at a playdate with a friend of mine who also has a Nikon D90 that the subject came up. This is my “photography friend.” We love to talk endlessly about our struggles and achievements with getting the perfect shot. We talk about the lenses we are trying out, speedlights, working with moving targets, and basically any tips or tricks we’ve discovered. Both of us are self-taught, so it’s very rewarding to triumph over an obstacle – and equally as frustrating when you can’t figure out what you are doing wrong! (In the interest of full disclosure, I did take a class in 2010, but found that I learned more about photoshop than about taking the actual shot. Tragically, I don’t use Photoshop. I use Aperture. Sad Panda!)
So anyway, I am at her house, and we’re talking about making the big jump to manual, and how nervewracking it is. And how once you’re in manual – you can’t just hand off your camera to someone else at a party or something and say “Hey! Take a picture of me!” And she says to me, “Well, even if I was in full auto, I couldn’t just hand my camera off because I do this crazy back focus thing now.”
This is me: “??!!?”
She says, “Oh yeah! I found this amazing website called Clickin’ Moms! I signed up for the trial period of a week and really committed myself to getting the most out of it, and found all these amazing tips and tricks. You should take a look at it.”
So off I go!
Turns out that back in March of 2008, a professional photographer named Kendra Okolita established Clickin Moms as a safe place for women to share their photos and passion for photography. It used to be made up of about 100 women – but in the last four years it’s grown to nearly 9000 members – and thankfully, it hasn’t lost the warmth and camaraderie of a small community.
This community is described on the site as “artists, hobbyists and professional photographers,” which basically means that there are people from all walks of life and all levels of experience on there. The first thing I noticed when I started poking around the forums was that they lacked the snobbery and elitism found on so many other enthusiast websites. You know what I mean? It’s extremely warm and friendly there. What a nice feeling to know that you aren’t going to get made fun of, or looked down upon because you don’t know the technical term for something. Otherwise, how are you supposed to learn? For instance, when I first started taking pictures, I didn’t know what bokeh was. I knew I wanted my pictures to have the subject in sharp focus and the background to be blurry. ButI had no idea how to achieve that effect. How lovely it would have been to have a resource where I could ask, “How the heck do I do that?” and not worry about being looked down upon, or flat out ignored for being a rube. This is the advantage to having all levels of experience in one place. Layman’s terms! You’ve heard the phrase, “There are no stupid questions,” right? It rings true here. Your question may help someone else who is wondering the same thing. I saw people asking things like “Hey, how do I get my subject’s skin to look all velvety?” and people took the time to answer them in detail, guiding them through camera settings and after effects.
BOKEHHHHH Photo: Kristen Rutherford
Within the first week of having access to the forums, I learned how to back focus, found someone sharing a great work flow for Aperture, and a step by step guide to making that scary switch to manual.
And DUDES, I haven’t even scratched the surface of the forums! I’ve been working my way through ONE sticky post called “CM New Member Guide – UPDATED.” – It’s a comprehensive guide to Clickin’ Moms meant to help new members feel less overwhelmed. (Meanwhile, I feel overwhelmed just trying to tell you about how awesome this website is.) Within this post, written by a CM Pro Mentor, it’s suggested you check out the following tutorials:
Learning to shoot Manual Skinny Wednesday: The Basics of Skin Color Correction Metering Tutorial Let’s talk focus Using curves to get that “creamy” skintone…. Lesson/Challenge on getting proper exposure Natural light during the day Sharpening Images Tutorial: Making grass and colorful clothes POP!!! Catchlight lesson Relationship Between ISO, Aperture & Shutter Speed Masking Basics Tutorial
DON’T YOU WANT TO DO/LEARN ALL OF THESE THINGS? I DO! Even if I forget my address and home phone number because I have all of these awesome new facts to stuff in my brain, it will be worth it. (And besides, I can always ask Siri to tell me my address and phone number.)
If you are a hobbyist and decide that you want to take it to the next level, there are guides to going pro. There are tons of business tips and workshops, as well as support from professional photographers. In 2010 Clickin Moms established CMPro – a place for professional, more advanced photographers to discuss their craft in a warm and friendly environment. I love this definition from the website: “the mark of professionalism is defined not by a business license but by the mastery of the craft.”
The Clickin’ Moms blog is free, and if you are into photography at all, I highly suggest you put it on your RSS, because it’s quite inspirational and features fantastic interviews with professional photographers, as well as interesting photo challenges. If you want to dive in, read the forums, and participate, you must pay to join the community. I recommend you take the plunge. The price of a lifetime membership is ONE THIRD of the price I paid for a class that I got maybe 2 things out of – but you can pay for a week, 6 months, or a year.
Here’s some good news! I contacted some of the amazing women that run Clickin’ Moms, and they agreed to do a giveaway! So, go right now to Clickin Moms, and put in the code GEEKMOMTRIAL and you will get a 7 day trial period. You can learn so much in 7 days.
BUT WAIT, THERE’S MORE!
Someone’s going to win a 6 month membership at Clickin Moms! I know! WUT!??!
This is the deal: to win the 6 months, you have to be a new member. So if you’ve joined recently, or you’ve always been meaning to join – now is a great time to do it! (and yes, if you do the free trial, you are eligible as a “new member.”) Once you’ve joined, or have used the free trial coupon — go like the Clickin Moms Facebook page, and then let me know that you did it in the comments here at Geek Mom. We’ll choose someone from our comments in a random drawing as our winner!
I’m so excited about this, and I can’t wait to see you guys over there. Have fun, get inspired, and happy clicking!