STICKY:  Canon DSLRs and Lenses 101

Thank you! This has been SO helpful. My first camera will be here in two days I have poured over this!

I really appreciate the time and effort that you put into this for us newbies.

Great forum. My sincere thanks.

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hi I am going to buy my first dslr sometime in the next 2 months. I have decided to buy the 600D/T3i but I am not sure about buying the 18-55mm kit lens or buying another instead. I will be taking photos of course as well as videos. so I want a lens thats not to large in size but has some zoom to it. the 18-55mm lens focus ring kinda looks cheap compared to other lenses. any recommendations would be great.

JohnnyJon, I would suggest trying to go for the t4i in the kit with the 18-135mm STM lens, if you can afford it ofcourse. Will cover you for picture taking and video really well. I hear the lens is a really nice starter lens, and the t4i has better autofocus and other features over the t2i and t3i.

Yarik wrote in post #15562385
JohnnyJon, I would suggest trying to go for the t4i in the kit with the 18-135mm STM lens, if you can afford it ofcourse. Will cover you for picture taking and video really well. I hear the lens is a really nice starter lens, and the t4i has better autofocus and other features over the t2i and t3i.

After seeing how auto focus doesn't have a smooth transition I am gonna have to learn manual focus in video record. I may go with 18-135 instead of 18-55mm.

Thank You, You explained topics in a simple and easy to understand format for a newbe like me this was very helpfull Thanks Again
JohnMD

To Bill NG, Thank you for taking the time to post this amazingly detailed explanation.
It is very helpful.

I am new to this forum, so hopefully I am posting this correctly.

Dee

I have just came over from the film world and though I knew a lot. Your initial post explained so many things I needed to know, I feel there is hope for me to become a good photographer.

Bill

Hi. I thot I'd pose this question here since I'm too lazy to look for a thread on it...

I have a CMOS question as it relates to noise. I understand the concept mostly from my silver/film experience with photography being old skool...while nobody would shoot a portrait in the old days with anything greater than ISO 200 (I used kodak VPS (160 ISO) exclusively or at worst their 400 in low light conditions...and with product photography I was a fan of Ektar 25.

I haven't graduated into a good and full understanding of DSLR yet and while I continue to upgrade just because, I've always wondered what the correlation of the CMOS is to the noise as the apparent ISO is increased. While with film the correlation was simple and correspondingly so with the resolution: nobody expected "grain" from an iSO 400 or less film and nobody expected to NOT have grain with 1600+ ISO film. Now that this 'function' is really a DIGITAL sensitivity setting, I'm curious what the CMOS variable brings to the table.

Bear in mind that I do not push the issue much given the type of shooting I do now, but everyone can appreciate the qualitative difference between an 8.1 MP compact and, say, my 18 MP 7d's CMOS.

Does that sensitivety increase or actually moderate noise at higher apparent ISO levels?

Coyote ESQ: You'll find that ISO-related noise in the digital sensor world acts much in the same way that it did in the film world (and I'm one of the old-timers that did a dozen years of film before moving to digital).

A bump in ISO on your DSLR corresponds to a bump in "gain" (voltage/current) on the sensor. This creates a bit of interference at the photosites on your sensor (the light sensors that ultimately read the "scene" and are turned into pixels) which often looks like grain/snow that's very simliar to high ISO film. A secondary aspect of digital noise that doesn't mimic film, is the color variation.

There is a direct correlation on digital between photosite density and noise. If you have a 12MP crop-sensor camera and a 12MP full-frame camera - with all other things being equal (same sensor manufacturer and technology), the full-frame camera will have considerably less noise at all ISO levels because the distance between each photosite on the sensor reduces the interference at each site - effectively making cleaner/less-noisy photos.

This is why early full-frame cameras like 5D Mark-I, that had less pixel-density than the current 5D Mark-III, have arguably cleaner high-ISO photos. On the other hand, camera manufacturers are always improving their in-camera noise-reduction software as well as their sensor technology. So noise, even within same-sized sensors, is much better handled today on a T5i than it was on my Digital Rebel (300D) from a decade ago.

Bill Ng wrote in post #15872342
There is a direct correlation on digital between photosite density and noise. If you have a 12MP crop-sensor camera and a 12MP full-frame camera - with all other things being equal (same sensor manufacturer and technology), the full-frame camera will have considerably less noise at all ISO levels because the distance between each photosite on the sensor reduces the interference at each site - effectively making cleaner/less-noisy photos.

This is why early full-frame cameras like 5D Mark-I, that had less pixel-density than the current 5D Mark-III, have arguably cleaner high-ISO photos. On the other hand, camera manufacturers are always improving their in-camera noise-reduction software as well as their sensor technology. So noise, even within same-sized sensors, is much better handled today on a T5i than it was on my Digital Rebel (300D) from a decade ago.

Not sure that I buy that argument!
There is a different concept than the above 'distance between each photosite' hypothesis, that explains the signal-to-noise characteristics at play...

• The larger area photosite, when the total pixel count is lower for the same sized total frame area, allows more photons to strike a given photosite thereby causing a greater degree of signal to be generated vs. the fundamental noise inherent to the circuit.

• Reduction of fundmental noise characteristics of the circuits used in signal generation and processing.
  
• Improvement of noise reduction processing methodologies designed into the signal processing circuitry.

I agree. Zoom numbers are meaningless. I agree that the old standard is that the 50 is "your" view of the world...that said, as you go up in numbers it is like putting a blinder on that would restrict your "view" but at the same time make it closer...much like looking thru a binocular set. The wider that 50 your lense goes means you are some peripheral "vision" to your image, like staring at something and capturing some of the stuff you are not staring at, if you will.

So if I'm tracking, the correlation is the same, if you will, and the real variable now is the cameras on board ability to mitigate the noise? Film would just be film, but in digital, the latest software interpreting the noise is key.

My 7d has never disappointed, but in low light it kicks butt on my 50d for results (unmodified), and therefore it not just the 18mp sensor, it's the interpretation of the data too.

Hi, I used to be a 35mm photography enthusiast... many, many years ago. Now I am a newbie digital photography hobbyest (just got my Canon Rebel). I thoroughly enjoyed the primer and, Bill, you deserve serious thanks for taking the time to help us neophytes The information was presented in a clear and logical manner and, for me, served as an excellent refresher.

I do have a question concerning terminology. When changing from a higher aperture number value to a lower aperture number (i.e. f/16 -> f/5.6) is that known as "stopping down" the aperture or is it the reverse that is known by that term? Also, is there a term for the opposite? I always thought "stopping down" was when you went from a larger aperture opening to a smaller aperture opening. I don't recall a term for going in the opposite direction. I could have likely Googled this, but I just joined the Forum today and thought other novices like myself might benefit from an answer - after all, if you're gonna walk the walk you should be able to talk the talk too

Javaman1216 wrote in post #15935666
When changing from a higher aperture number value to a lower aperture number (i.e. f/16 -> f/5.6) is that known as "stopping down" the aperture or is it the reverse that is known by that term? Also, is there a term for the opposite? I always thought "stopping down" was when you went from a larger aperture opening to a smaller aperture opening. I don't recall a term for going in the opposite direction.

Discussion of aperture (size of opening) or f/number (the numerical value)...

• we usually refer to the magnitude of the opening , not the value of the number
  
• the biggest achievable opening for a lens (smallest magnitude f/number, e.g. f/2) is 'wide open', and
  
• as the opening gets smaller and smaller in diameter (bigger magnitude f/number, e.g. f/22) it is 'stopped down'.
  

• 'stop down' when you make the opening smaller (e.g. from f/4 to f/8), and you
  
• 'open up' when you make the opening larger (e.g. f/16 to f/8).