Lens question

[kharypayt37]

I currently have a t6i body with a 55-250mm lens. I mainly take sports pictures/videos (American football), and I am wondering which lens I should upgrade to. I am looking for an investment piece that will suit me down the line should i upgrade my camera. From research the past few days, i have focused on the 70-200mm f/4 IS II. This has been the clear-cut favorite (according to the sources ive looked at). However, i am not sure if i should opt for a lens like the 300mm as my current lens can deal with those closer shots.

i appreciate any advice!

[jrhoffman75]

Exactly. So either a poor answer would be given or you would need to know that crop factor exists and ask the individual what camera they have. 

[jrhoffman75]

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@ebiggs1 wrote:

"If someone is specifically looking for a standard lens (in terms of field of view), they do need to look at focal length and understand that a 50mm is standard FOV on full frame, but short telephoto on APS-C."

Ricky this is where it goes south. Unless you are comparing and 'thinking' in FF camera theory and terms the crop factor is meaningless. Not how does it work on somebodies FF camera that you may never own. Why?  Because you probably purchased the 17-55mm kit lens. If you are a crop camera photographer you probably notice at 35mm my lens gives me a normal perspective.  You don't think what the heck is this kit lens FL on a FF camera.  

You see there is a "crop factor" in reverse for the medium format guys.  However, they never seem to see the need to use it. The 645 medium format has a "crop factor", it is .62 but I bet you hardly ever heard of it or ever see people use it. That's because they don't relate back to 35mm film or FF format. Crop factor was a term created by the old 35mm film people that had to get used to the, then new, smaller digital sensors being made. It was and has been a confusing term ever since.

BTW, your iphone has a crop factor!  Do you know what it is?

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[ebiggs1]

I did not say it didn't exist. This is, again, an attempt, likely from the advertising department, to get 35mm FF people into a different sensor size camera. It, in no way justifies it.

If you ever worked for a large professional company that used every conceivable photographic gear there is, you would more likely see the meaningless of crop factor.  Never did the 8x10 guys, or medium guys, ask or think, what lens in 35mm film format do I need to get xxx results.

If the old guys stopped using it, it would go away but they don't.  They keep it going, not new folks.

[ebiggs1]

John Hoffman
Conway, NH

I must say some of you sure spend a lot of time on, and searching the ole inner web! 

[MikeSowsun]

The actual origins of "Crop Factor" come from the APS FILM cameras introduced in 1996. 

Canon literature never really mentioned "Crop Factor". The camera sales people used "Crop Factor" a lot while trying to explain how the EF lenses used on the APS Film cameras are going to look "different" than what we were used to. 

Here is a page from the EOS IX manual where I have added the image size and crop factor:

[jrhoffman75]

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@ebiggs1 wrote:

John Hoffman
Conway, NH

I must say some of you sure spend a lot of time on, and searching the ole inner web! 

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Not really. It was a topic at a recent training session at our camera club and I borrowed the slide.

[rs-eos]

I have used an APS-C (Rebel T4i) prior to the FF cameras.  One exercize I did prior to the move was to see what was the equivalent field of view.  Vast majority of images were at 56 mm because I was mostly at 35mm on the 18-135 kit lens.   This led me to pick up a single 50mm lens with the FF gear.

I also know the crop factor on my iPhone 12 Pro, video gear, etc.  And have also read articles regarding the "reverse" crop factor when speaking to medium format.

I stand by my statement above.  IMO, it's still useful information to know.