Zooms unnecessary with high megapixels & crops out of primes

OK, Y'all win. I' gonna go buy a 24L and sell all of the other lenses.. And then go sit in the back of the stadium and crop the pictures down..

Horsepuckies! You guys sound like you get every shot perfectly framed and never crop. Digital zoom is just another word for cropping.

Example below, shot at 300mm and half the image was cropped out. If I had a ronco presto chango 500mm I would not have had to crop. Since they don't make one we will call that a digital zoom.

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brennanyama wrote in post #15056977
if you really think about how the camera works, it's not the megapixels that grant great cropping ability, it's the size of the sensor. The megapixels only determine the size of the image generated by the sensor following after processing of the image. The higher the megapixels, the higher the "density" of the image (higher number of image area per amount of sensor size), but the actual quality of the image is determined by the sensor size.

Take, for example, utilizing a crop sensor and a full frame. You use the 1.6 field of view crop factor because the sensor on an APS-C camera is 1.6 times smaller than the sensor on a full frame--this achieves the effect of making an image from an APS-C camera appeared more "zoomed in", which people may view as a valuable attribute; however, the reality is that cropping the final image from a full frame sensor down to 1.6 times it's original diagonal length achieves the exact same effect as taking a picture with an APS-C camera. The only advantage of an APS-C camera is that you are able to achieve high density images more easily (high number of megapixels per area of sensor). Due to the squaring effect (linear increases in length amount to exponential increases in area), in order to retain the same resolution you get from an 18MP APS-C camera, you'll need to have a full frame sensor that outputs to ~47 megapixels (hopefully I did that right).

Until we get a 47MP full frame (which is pretty inpractical), the 18MP APS-C will continue to have a "resolution advantage" (although be careful with the term "resolution", its actually a politically incorrect term, "pixel density" is more correct) over full frame cameras. This arguably makes them better for taking giving one a range advantage with the 1.6 FOVCF, but, for the reasons I just explained, density only helps so much, as you're typically more limited by the sharpness of your lens. If density were more important than sensor size, we would all be using cell phone cameras with ultra high megapixels (okay maybe not, but you get the point).

All of this being said, does the statement "zoom's aren't necessary anymore as we can crop easily with those full frame sensors" hold much water? In a way, yes it does, granted that you're willing to live with an image that does not live up to its full potential. again, pixel density aside, cropping the final image is effectively exactly what we do with APS-C cameras; however, if you have the ability to zoom in (or shoot at longer focal lengths), you retain the (relatively) full quality of the image whist not having to move in closer to your subject. Also, different focal lengths meter a scene differently (subject to background ratio), and obviously grant different depths of field.

Really ? [Based strictly off the first paragraph] OK- you go grab a 5D classic- it's got that large sensor you want- and a 300mm lens.. I'll take a 7D, with a 300mm lens.. We both take a picture of the moon, assuming that we are both still here on earth.. Then we both crop the picture of the moon so that it fills the screen... OK... Better yet- let's both print them out so that the moon fills, say a 8x10 print. Or maybe stretch it to an even larger dimension. Let's see which one looks better... Going by your assumption- your picture should look better because it's got the larger sensor..

Truth is - crops are good for certain things and full frame- is better at others.. Want proof- look at how many of the 1D series were crops ...

bigVinnie wrote in post #15057742
Horsepuckies! You guys sound like you get every shot perfectly framed and never crop. Digital zoom is just another word for cropping.

Example below, shot at 300mm and half the image was cropped out. If I had a ronco presto chango 500mm I would not have had to crop. Since they don't make one we will call that a digital zoom.

yeah everyone crops...but what the op is talking about is entirely different...he's saying take that shot with an 85mm lens...and then crop it to what you've got...

or at least that's the impression i got when he's talking about eagle shots with an 85mm lens

I think numerous good points have already been made but would like to give my perspective, preferring zooms over primes. They each have their own place though!

1) I don't agree using primes will "make" you a better photographer as one poster stated. You just have to walk more or crop more. In fact, it could be argued or even shown you can be a better photographer using zooms in this sense.

Ex) You put a photog in a crowd of active kids, the photog with the zoom lens is going to come away with the better pictures in most instances.


Yes you could "crop" images in getting the same composition a zoom lens could have rendered immediately, HOWEVER:

a) What about time/cost prohibitive scenarios?
b) You cannot pencil in the kid or kids who got cut off because you weren't able to move back fast enough with
your prime!
c) You might have desired shooting from a low perspective (laying on ground). A prime would be highly
restrictive in this case versus a zoom.

Now you could set up far enough away with your prime that "cropping" would theoretically always be an option. But you are completely limited to what is directly in front of you. What happens when something interesting occurs on the opposite side or you have kids running between you and your desired subject(s)?


2) Primes are better at:

a) isolating the subject with shallow DOF
b) better in low light
c) typically sharper.

All of which is irrelevant to this thread.


3) If they ever invent zoom lenses that are equal at:

a) DOF
b) low light
c) sharpness.

Then you'll see less usage of primes....


God Bless

bigVinnie wrote in post #15057742
Horsepuckies! You guys sound like you get every shot perfectly framed and never crop. Digital zoom is just another word for cropping.

Example below, shot at 300mm and half the image was cropped out. If I had a ronco presto chango 500mm I would not have had to crop. Since they don't make one we will call that a digital zoom.

Big Vinnie,

Your method of shooting with the 300, then cropping, resulted in a very effective image.

However, with the 500mm, you could have blurred out the background fence to a greater degree, given the same aperture and shooting position. There are some elements in an image that cannot be best captured by shooting wider, then cropping.

For me, primes are more comfortable to use (they are pretty light and you know your frames). But it definetly depends on a situations, for example, i love the primes like 28, 35 or 50mm, but when it comes to telephoto, zooms are way easier to use, without being forced to walk like an idiot. Also telephoto zooms doesn't change the perspective so much, images taken on 24mm and on 105mm looks totally different, while those on 70 and 200 are quite similar, of course 200mm gives more flatterned image, but the difference is not so big.

So, primes like 24L, 35L, 50L or 85L makes a lot of sence to me, but something like 200/2.8 or 400/5,6 doesn't.

_igi wrote in post #15058491
..... Also telephoto zooms doesn't change the perspective so much, images taken on 24mm and on 105mm looks totally different, while those on 70 and 200 are quite similar, of course 200mm gives more flatterned image, but the difference is not so big.

Focal lengths, in themselves, have nothing at all to do with perspective in images. It's the distances between the camera (or your eye) and the various elements of the scene in front of you that affects the perspective.

Please read our "sticky" (found in the General Photography Talk forum) tutorial titled Perspective Control in Images - Focal Length or Distance?.

Tom Reichner wrote in post #15058033
Big Vinnie,
However, with the 500mm, you could have blurred out the background fence to a greater degree, given the same aperture and shooting position....

True, except for the 10 seconds later when I had to roll the lens back to 70mm to get the shot. Since the best tool for the job is a 70-300 zoom I'm stuck with f/5.6 and cropping some times.

I would much prefer to be using a prime. I do when I can. I have however been forced to do what the OP was talking about and using a shorter prime and cropping the crap out of it. With the high quality sensors that are coming out now I can see more people taking that approach. Not what I would recommend it but depending on the circumstances it can be an option.