Longer Lens or Crop Sensor

[Braineack]

Just to clarify: A crop sensor does NOT give you 'more reach'. The crop factor simply refers to the field of view, and NOT any extra magnification. In other words, on a crops sensor, a 100mm lens is considered to a 150mm lens, however what this means is that when you mount a 100mm lens on a crop-sensor body, it gives you a field of view similar to that of a 150mm lens on a full-frame body. It does not magnify it.

he didn't say extra magnification or focal length, he said extra reach.

what if we defined "reach" as a narrower FOV (as it always is) and not focal length or magnification (not that anyone actually does). now what?

I'm going to quote you

"The crop factor simply refers to the field of view"

now:

"The reach factor simply refers to the field of view"

:shock:

Erhmmm... how'zat again?

define reach.


true statement:
all things being equal crop sensors give you extra reach.

false statement:
all things being equal crop sensors give you extra focal length.

false statement:
all things being equal crop sensors give you extra magnification.

 

[tirediron]

...The advantage is a myth?! the advantage is real...

what complete disingenuous drivel.

How about we go about this a different way:

You have two cameras; one crop and one ff. Both with the same lens.

there's a bird on a post in front of you, you look through each viewfinder and decide to shoot with the crop sensor because the bird fills the frame -- even though we are using the same lens.

what do you call this effect?

we know it's not reach, cause reach is a myth. so what should ever photographer in the world start calling it?

"Illusion" is a good word. I can live with that.

My initial post may not have been the most accurate; I was simply attempting to refute the common misconception that a lens of XXX mm when placed on a crop-sensor camera will give you the same results as one of [approximately] one third less on a full frame camera. For the sake of simple math, it's commonly believed that placing a 100mm lens on an APS-C / DX body will give you a result similar to that of a 150mm lens on an FF body. That is simply not the case.

The various definitions of 'reach' notwithstanding, and assuming both bodies had the same pixel count on the sensors, then what you will get when you put your 100mm lens on a crop-sensor camera is an image which has a field of view equivalent to that of a 150mm lens used on a full-frame camera. Yes, it fills the frame on the crop-sensor camera just like on the FF body. Why? BECAUSE IT"S A SMALLER FRICK'IN FRAME!

 

[Alexr25]

My initial post may not have been the most accurate; I was simply attempting to refute the common misconception that a lens of XXX mm when placed on a crop-sensor camera will give you the same results as one of [approximately] one third less on a full frame camera. For the sake of simple math, it's commonly believed that placing a 100mm lens on an APS-C / DX body will give you a result similar to that of a 150mm lens on an FF body. That is simply not the case.

Actually IT IS THE CASE, at least it is in terms of field of view which is the major factor in determining lens choice. Depth of field will be different but generally its the field of view that is the important parameter.

 

[Braineack]

The various definitions of 'reach' notwithstanding, and assuming both bodies had the same pixel count on the sensors, then what you will get when you put your 100mm lens on a crop-sensor camera is an image which has a field of view equivalent to that of a 150mm lens used on a full-frame camera. Yes, it fills the frame on the crop-sensor camera just like on the FF body. Why? BECAUSE IT"S A SMALLER FRICK'IN FRAME!

and thus extra reach. why argue this?

 

[tirediron]

Okay........ I guess I genuinely don't understand "reach".

 

[astroNikon]

I need longer reach. So in the coming year I will either get a longer lens or a crop senor body to go with the glass I have. I am curious what all of you think about the trade-offs for each strategy.

A little background. I have a 6D mark II and the 70-200 2.8 L USM II with the 2x teleconverter. I shoot sports inside and out and would like to have longer reach for wildlife photography.

My perception is that the crop sensor would be the less expensive option but a longer lens on a full frame is technically better. I am concerned about noise at high ISO on the likes of the 7D m II or the 80D (assuming those are the best Canon crop sensor options).

Thoughts?

Back to the OPs original question.

I have BOTH, for totally, but the same reasons.
D750 (24mp) and D7200 (24mp) ( had a D500 - 20mp, and previous a D7000 - 16mp)

FF - portraiture photography
FF - attach to my telescope to get larger swaths of sky
CROP - attached to my telescope to get smaller segments of sky

SPORTS - this is dependent upon a few factors. For instance on a Crop D7200 I want to have a wide focal length. Say I use my 80-200. It's actually FOV 120-300. Good for the long end @300, but horrible for the short end @120 if I'm near the side line. If I'm in the stands it's okay; of course the FullFrame is 80 on the short end great for the close sidelines but many time not enough reach.

But then I can use a 70-300 on the FullFrame for the same effects on the sideline and cover more focal range than the Crop. And 300mm actually is quite good for a full size football/soccer field. ... for a 1 lens setup. If you use a 2 camera setup I'd use my 24-85 on FF and 80-200 on Crop.

Now let's throw a monkey wrench into that concept.
If you are shooting in the evening or lower light situations the FF will have the advantage. My D500 I shot at an evening soccer game under the Bright LED lights. It did "okay" on the edge of getting bad. The FF had no problems. For the extra $$ the D500 was I swapped to a D7200 instead as it was a little less in lower light but at that point the FF with a good 70-300 is the better option anyways ... unless you're after FPS.

Aircraft/Birding - using my 150-600 the Crop definitely has the advantage there of 900mm FOV unless it's early in the morning, or later in the evening or heavily overcast .. ie, the lower light issue.

So the answer is ... it depends. In perfect lighting the crop will have certain advantages.

Of course a teleconverter can mess with that formula too.

 

[BananaRepublic]

I watched a few youtube vids on this and it took me a while to get past what the stooges and the ivory tower experts were saying but I think I have a vague understanding now. I was fine with the field of view concept before hand but one guy spoke about multiply your lens aperture by the sensor crop factor. Is the aperature concept an important factor in this thread , ie, reach/magnification or is it a seperate issue.

 

[Overread]

This is one of those topics where you can take it three ways

1) The simplistic way - angle of view comparisons only and a casual understanding - perfectly fine for 99.9% of photographers and photography

2) Full physics understanding of what is going on

3) A half and half approach that will often make little to no sense. This is because you'll be adding in real physics elements to simplified descriptions that "carry the point" but are factually wrong.

The aperture aspect is one such area where this gets rather convoluted and confusing. Suffice it to say that crop factor will have an influence on your depth of field (as a result of the circle of confusion changing because of the format size change); however by and large its a negligible difference. The only photographers that ever tend to notice are macro photographers.

Also whilst the depth of field changes the aperture isn't changing - it remains the same. You know this to be true because otherwise things like external light-meters wouldn't work

 

[Braineack]

Okay........ I guess I genuinely don't understand "reach".

while I think it's fair we all understand the real physics involved and why and what's going on here; I like to define "reach" as the ability to natively fill the frame with the subject.

example: I've been seeing some awesome birding images out of a 300mm lens with the 4/3 E-M5. At 300mm, that thing has a lot more reach than 300mm on my D800...

you can't say that "reach is a myth" because it's real. Call it "optical cropping" or what have you, but to say it's not real is disingenuous. I can't crop a 36MP image down by a factor of 2 and end up with 40MP -- the math don't add up.

 

[john.margetts]

Okay........ I guess I genuinely don't understand "reach".

It's a bit like sharpness that people bat on about. There is no property of either a lens or an image that you can define as sharpness - sharpness is an amalgam of various properties rather than a property itself. I think 'reach' is another amalgam - you can define the various properties that contribute to the non-property 'reach' but never actually really define 'reach' itself.

 

[Derrel]

Okay........ I guess I genuinely don't understand "reach".

while I think it's fair we all understand the real physics involved and why and what's going on here; I like to define "reach" as the ability to natively fill the frame with the subject.

example: I've been seeing some awesome birding images out of a 300mm lens with the 4/3 E-M5. At 300mm, that thing has a lot more reach than 300mm on my D800...

you can't say that "reach is a myth" because it's real. Call it "optical cropping" or what have you, but to say it's not real is disingenuous. I can't crop a 36MP image down by a factor of 2 and end up with 40MP -- the math don't add up.

I agree with this..the Nikon D2x which has an APS-C sensor with a 1.5x FOV factor and my 400mm lens, I get top speed of 5.0 frames per second, and an X by Y field of view at a baseball game. Using that same camera and sensor in high-speed crop mode, the FOV factor becomes 2.0, and the frame-per-second rate goes up to 8.2 f.p.s., and the lens frames EVEN-more tightly!

The same thing can be done on newer Nikon d-slr cameras, like for example the D610 or D800 full-frame bodies can shoot in what Nikon calls FX (full-frame) format, or also in DX format. Using the _same lens_, like say an 85mm or a 105mm, when the camera is shooting in full-frame mode, the field of view is relatively wide; when the camera is switched to DX mode, the field of view of the 85mm or 105mm lens is reduced commensurately.

Anyway, to the OP: I'd look into the 150-600mm zoom lens as an affordable, long, stabilized lens for birds. Glass first!

 

[BananaRepublic]

On a APS - C with a DX lens does the FOV calculation apply or is only valid it for FX lenes on cropped sensor bodys

 

[astroNikon]

On a APS - C with a DX lens does the FOV calculation apply or is only valid it for FX lenes on cropped sensor bodys

A 50mm DX lens is the same as a 50mm FX lens in focal length. Just that the DX lens has less diameter glass to produce less diameter image as the DX sensor is smaller than an FX sensor. This manufacturing allows a less costly lens, smaller and lighter.

but to calculate true FOV one uses (for Nikon DX) 1.5x the lens focal length irregardless if it's a DX specific or FX lens.

So on a DX crop body use 1.5x the focal length .. whether 35mm, 50mm, 85mm, etc. irregardless if the lens was a specific DX or FX made lens to cover a larger or smaller sensor image circle.

 

[Derrel]

On a APS - C with a DX lens does the FOV calculation apply or is only valid it for FX lenes on cropped sensor bodys

SAME FOV, on a DX- or APS-C camerta, when using either a DX lens or a lens that covers full-frame...the DX-Nikkor 35mm f/1.8 AF-S gives the same field of view as say, the 35mm f/2 AF-D Nikkor, when used on a DX camera.

 

[photoflyer]

Very informative (and spirited) dialogue. Clearly fast glass is the best and much more expensive solution.

Having a good second body is a plus though.

I am told Sony APS-C sensors are very good at high ISO and that there is an adapter that would enable it to work with L series Canon glass. Anyone have experience or thoughts on this?