Photography Lessons

jra,

Thanks! That's what I'm looking for. Yeah, I goofed. I'll fix it immediately. When I wrote that paragraph my inner editor was screaming, "Hey! you better look that up. It doesn't sound right." I told myself I'd check it later, but then I forgot. Upon further review I'll restate that every doubling or halving of ISO is equal to one full stop. so going from 100 to 400 ISO is only two stops (100 to 200 is one stop, 200-400 is another stop).

themadman,

Wow, if you find the time to read the whole thing I'd love to hear your opinions.

xtreme,

Glad to help you out.

"The two controls a camera has over exposure are aperture and shutter speed."

and ISO ........... but that's silent.

:p

RbnDave wrote in post #11446371
So is that it? Any critiques? This series is a work in progress. I am planning on going back and editing most of the lessons at some point.

Writing something like this without any outside input is a challenge.

Looking at the above post about ISO, I'd say you want to take some time to read up on this.

First, the nature of digital ISO is not about sensitivity to light, it's about amplification applied to the signal collected by the sensor. Film ISO was about sensitivity, digital is about amplification. I'm just saying it's good to get accurate with your info! High ISO film actually uses "grain" that is more sensitive to light in the emulsion of the film itself so, in a very real way, it has "collected" more light.

Second, the point made by the above poster is correct -- a "stop up" of ISO means a doubling of signal amplification in the same way that a stop up of shutter speed is a doubling of speed and a stop open of the aperture means twice a much light is being collected. So, for ISO, "full" stops are 100, 200, 400, 800, 1600, 3200 -- as far as the camera is capable of. Each stop doubles the amplification of the signal. And then, there are ISO valuse that you can use that combine electronic amplification with software amplification, but the point is still that the same light is being collected by the sensor and being amplified, rather than the idea that the sensor is somehow more "sensitive" to light.

Tony,

Thanks for the input. In the actual article I go on extensively about how ISO is NOT sensitivity but amplification. I spend about four paragraphs on that subject. I cover why this causes artifacting at high ISO settings in shadow areas. This is a quote of the paragraph following the one you're talking about.

"Here’s the big catch when it comes to ISO, you are not actually turning up the sensitivity of the image sensor. You are turning up the gain. There is a big difference. With a high ISO your image sensor doesn’t miraculously find a better way to see. What happens as you raise ISO is the million little volt meters we talked about earlier add some amplification to their signals. This trick of electronics does a great job brightening midtones and highlights, but it doesn’t do such a stunning job with shadow detail. Remember, your image sensor already has some problems when dealing with shadows. Adding amplification doesn’t always solve those problems. A lot of times it actually amplifies them. That’s where you can get a lot of digital noise — using a high ISO and taking photos of dark objects or deep shadows."

I am wondering from an editing standpoint if that is too much information for a beginner. Where does one draw the line between writing a beginners tutorial and intermediate? I suppose it depends how motivated the reader is.

Dave

RbnDave wrote in post #11451320
Tony,

Thanks for the input. In the actual article I go on extensively about how ISO is NOT sensitivity but amplification. I spend about four paragraphs on that subject. I cover why this causes artifacting at high ISO settings in shadow areas. This is a quote of the paragraph following the one you're talking about.

"Here’s the big catch when it comes to ISO, you are not actually turning up the sensitivity of the image sensor. You are turning up the gain. There is a big difference. With a high ISO your image sensor doesn’t miraculously find a better way to see. What happens as you raise ISO is the million little volt meters we talked about earlier add some amplification to their signals. This trick of electronics does a great job brightening midtones and highlights, but it doesn’t do such a stunning job with shadow detail. Remember, your image sensor already has some problems when dealing with shadows. Adding amplification doesn’t always solve those problems. A lot of times it actually amplifies them. That’s where you can get a lot of digital noise — using a high ISO and taking photos of dark objects or deep shadows."

I am wondering from an editing standpoint if that is too much information for a beginner. Where does one draw the line between writing a beginners tutorial and intermediate? I suppose it depends how motivated the reader is.

Dave

Ah, cool, I haven't had the time to wade through it all, so I was just reacting to the paragraph that got quoted. You cleared that up!

As far as "how much is too much" for beginners, that's a good question -- I'd say "keep it simple" and not too technical, but have at least a way that people can get more info? For example, people who are coming from shooting film will often totally misunderstand the nature of digital ISO compared to film ISO, will mix up grain with noise, will be afraid of anything higher than ISO 100 because of their film experience, all this stuff. It would be nice to maybe provide links for more info about this type of thing without drowning your readers with technical info!

Anyway, good for you for getting this together to help people!

Hey yeah, links are a good idea. I've found that Wikipedia actually has some great photography info. Lots of the time it's way to deep for a novice, but great study for more advanced photogs.

BTW, I rewrote the botched ISO paragraph. Here it is -- I hope it makes more sense now.

Your camera’s ISO setting often (sort of incorrectly as we’ll discuss later) defined as how sensitive your image sensor is to light. An ISO of 100 is less sensitive than ISO 200. Each 100 doubling of ISO value is equal to one stop of aperture or one stop of shutter speed. For example, let’s say you are shooting a football game on a cloudy day. You have a really expensive lens and you are shooting at f/2.8. Since it’s cloudy you notice that your shutter speed is only 1/60th second. Your photos aren’t coming out very crisp. The action on the field is just too fast for that slow shutter speed. Being a smart photographer you decide you want a faster shutter speed. Your lens is already dialed down to its fastest aperture. What else can you do? You turn up the ISO. Let’s say you dial up the ISO to 400. That’s two full stops faster than ISO 100 (going from 100 to 200 is one stop, from 200 to 400 is another stop). Now, with the same lighting you get camera settings f/2.8 and 1/250th. That’s fast enough for this action.

Here a link to the entire article about image sensors and ISO

I'll check it out when I have more time, but for beginner/intermediate - how about bullet points or summaries at the end of each section, with the key points that a beginner should get from that section in simple terms?

in other words, if you can make the point simply, but go into the "why" for intermediate readers, make it easier for beginners to skim when they get confused but get the main points across. Like, on the "what is aperture" page - the paragraph that says "So here is the important take away from my long, rambling aperture value explanation:" Rather than say that, have that summary in a box or bold or quoted (since I'm familiar with the wordpress formatting for quotes, it would probably be boxed/shaded). Do that for each section.

You know the old "tell them what you're going to tell them, tell them, tell them what you told them" format for presentations? Explain what the page is about. Go into that topic in detail. Then sum it all up in what every reader should take away from that section, even if they didn't understand every single part of WHY.

Explain in the intro that this is how you approach it, and beginners will feel more comfortable reading and knowing they don't have to comprehend every single piece of info you give them, you'll tell them what they should get out of it. And of course encourage them to come back later in their studies of photography to read it again and gain more of the details :P

took a quick peek, i enjoy the animated gifs for DOF discussion. Nice

RbnDave wrote in post #11451508
Hey yeah, links are a good idea. I've found that Wikipedia actually has some great photography info. Lots of the time it's way to deep for a novice, but great study for more advanced photogs.

BTW, I rewrote the botched ISO paragraph. Here it is -- I hope it makes more sense now.

Your camera’s ISO setting often (sort of incorrectly as we’ll discuss later) defined as how sensitive your image sensor is to light. An ISO of 100 is less sensitive than ISO 200. Each 100 doubling of ISO value is equal to one stop of aperture or one stop of shutter speed. For example, let’s say you are shooting a football game on a cloudy day. You have a really expensive lens and you are shooting at f/2.8. Since it’s cloudy you notice that your shutter speed is only 1/60th second. Your photos aren’t coming out very crisp. The action on the field is just too fast for that slow shutter speed. Being a smart photographer you decide you want a faster shutter speed. Your lens is already dialed down to its fastest aperture. What else can you do? You turn up the ISO. Let’s say you dial up the ISO to 400. That’s two full stops faster than ISO 100 (going from 100 to 200 is one stop, from 200 to 400 is another stop). Now, with the same lighting you get camera settings f/2.8 and 1/250th. That’s fast enough for this action.

Here a link to the entire article about image sensors and ISO

I think that is a reasonable way to explain how ISO can maintain desired exposure when needing faster shutter speeds in a low light situation.

'Understanding Exposure' by Bryan Peterson talks about ISO being the 3rd control.

Great stuff! Just started reading the intro and first lesson...had to take a minute to laugh when I got to the part of throwing a sack of puppies in a river. Disturbingly funny metaphor! Going to hug my spoiled puppy now before I read any more!

wow wonderful thanks for sharing. i am currently doing my course to get my diploma so the extra reading and stuff is very helpful thanks again

Can't wait to read through them! Thanks for posting!

Am trying to learn (and relearn) all the basics after many years. Stumbled across this thread and plan to read all of them, hopefully over the holiday slow times. Thank you for taking the time to share your knowledge with others.

Dave, I think this is a wonderful effort on your part. I stayed up late last night reading most of the chapters. You do a really great job with your stated goal of making photography straightforward and understandable. And you write and explain all this stuff well—I'm a writer, so I'd like to think I know a good one when I read one.

I won't comment on any of the actual content because there are others on POTN who are far more qualified than I am. However, I'd like to make one general suggestion about layout that will help:

You have a lot of great content, but the size of type and the way it is presented can be challenging to the photography neophyte. I would suggest a different background color, larger font, and using subheadings to organize the content within each lesson. Also, limiting the width of your paragraphs will also greatly help—this is why newspapers and magazines use column widths.

Snakedoc,

Thanks for the compliments and suggestions. I totally agree about changing the background color and layout. I want to find a better blog template. For now I am stuck with the hard to read background. There isn't a wordpress template with a white background that allows large photo posts. Hopefully something will change soon, or maybe I need to learn CSS.

I'm glad you like the writing. It's hard to right technical instructions without sounding like a computer.

K8et,

Thanks for the suggestions. I think I might add some summary bullet points.

I tried to layout each lesson like you suggest "tell them what you're going to tell them, tell them, tell them what you told them". When I was a flight instructor all our briefings were set up in that format. When I wrote the lessons I used that format to some extent, but i think by the end I was skipping the review portion. Maybe if I created some bullet points the review would be covered that way.

Whip,

Glad someone gets my sense of humor. Thanks