James809
Senior Member
Question as posted; what's the magic "reach" people talk about as an advantage or DX over FX? Angle of view is narrower, but what exactly is going on, and why is it considered "more reach?"
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Supposed "reach" advantage for DX vs FX; is it just the equivalence of digital zoom?
- Thread starter James809
- Start date
Solution
n057
Veteran Member
A duck, or maybe a lion or tiger. Thinking about it, you could walk closer to the tiger with an FX camera and "reach" closer to the tiger. Zoom with your feet, crop the scene in the viewfinder.
JC
Some cameras, some lenses, some computers
BirgerH
Veteran Member
Yes - it is - or actually the camera software does, because it is enlarging a smaller format to the same viewing size (final image) as the larger format.
Exactly... The "rest 3 times" magnification is made by software enlargement - which is, as the OP asked, simply digital zooming.
LordKOTL
Senior Member
LordKOTL
Senior Member
There's a few ways of looking at the "reach" aspect of the DX vs. FX thing.
One part is the pixels-on-subject, which I won't rehash.
There's also the angle-of-view. Please keep in mind I'm rounding here for simplicity and actual real-life circumstances.
A 500mm lens has a 5deg diagonal field of view on FX, and a 3.2 diagonal field of view on DX. A perfect lens match would be a 750mm on FX--which to my knowledge doesn't exist for Nikon. The closest is an 800mm lens, which is 3.1deg diagonal field of view.
If I needed a 3.2 degree diagonal angle of view to get a shot of the duck, and I wanted to get 24MP on it, for a DX camera I can do it with a 500mm lens--and I can get one for $1400 (the 200-500). On FX? I either crop and lose pixels, or I need a 750mm or better lens. If I use that 800m lens I'm looking at over $16,000.
Even though it changes the photos' aspects because you're not shooting from the same place, there was the aforementioned "getting closer" which might not be wise or feasible.
Solution
James809
Senior Member
So what I think I'm hearing is that "reach" isn't quite the right term, but it close enough describes in 1 word what's actually happening (given the almost 3 pages of responses here, there's obviously still some grey area). The advantages behind the term are real, though, and qualify the concept of DX being "better" for some applications than FX (using the term as an approximation, not an absolute).
Thanks all.
Thanks all.
LordKOTL
Senior Member
Kinda--at least in my opinion. As I mentioned in my other post, there's the crop way of looking at it--which has been discussed extensively, and the angle of view of a given lens on DX vs the lens that would give an equivalent angle of view on FX and the price difference. I think the latter is what was meant when "reach" was coined. i.e "To get this angle of view on FX, I'd need a lens that's 1.5x longer, which can be an imperial buttload more expensive".
Alex Permit
Senior Member
It's all well and good to discuss compare a DX image cropped from a FF camera to a DX image shot on a a native DX camera. But keep in mind the image you see in the viewfinder as well. In a FF DSLR, the cropped image you see in the viewfinder will be much smaller than than the image you see in a native DX camera.
BirgerH
Veteran Member
BirgerH
Veteran Member
That will have nothing to do with the image being cropped to DX.
If the viewfinder magnification in the two cameras are equal, the cropped part of the FX-viewfinder image will have same size as the DX viewfinder image.
Remember - the optical magnification (lens focal length) is not changed - so subjects will have same sizes.
JMD-70
Senior Member
Thus the D850 being a "Jack of All Trades" DSLR! This might get interesting!!
AwesomeIan
Senior Member
olyflyer
Forum Pro
I can't believe that this question is still asked in 2017. Hasn't this been answered several millions of times ever since digital cameras hit the consumer market?
Dogman Joe
Active member
There is no "camera software" that enlarges the image. Here is what the Nikon School's "Guide to Digital SLR Photography" says about FX vs. DX:
"But because the DX sensor covers a portion of the image that's transmitted by the lens, a "crop factor" is introduced - meaning that the smaller sensor trims the image a bit, capturing data from a slightly smaller area of the scene. The result is that the lens used on a DX-sensor camera will appear to magnify the image by 1.5 times. The key point, of course, is that with both sensors, DX and FX, what you see through the viewfinder is what you are capturing."
I say again, that the problem with reach is that many people think it equates to magnification. And it doesn't. Magnification, with cameras or binoculars, means that what you see appears 6, 9 or 12 times closer than what it is depending on whether the magnification value of the camera or binoculars is 6,9 or 12 power.
"But because the DX sensor covers a portion of the image that's transmitted by the lens, a "crop factor" is introduced - meaning that the smaller sensor trims the image a bit, capturing data from a slightly smaller area of the scene. The result is that the lens used on a DX-sensor camera will appear to magnify the image by 1.5 times. The key point, of course, is that with both sensors, DX and FX, what you see through the viewfinder is what you are capturing."
I say again, that the problem with reach is that many people think it equates to magnification. And it doesn't. Magnification, with cameras or binoculars, means that what you see appears 6, 9 or 12 times closer than what it is depending on whether the magnification value of the camera or binoculars is 6,9 or 12 power.
Alex Permit
Senior Member
What you say is true if the viewfinder magnification is the same. It is certainly not when comparing pro level cameras to each other:
D500 viewfinder magnification: 1.0x
D5 viewfinder magnification: 0.72x
D810 viewfinder magnification: 0.70x
We can use the above information to calculate an "effective viewfinder size" of each camera in DX mode
Effective size of D500 in DX mode: 0.66
Effective size of D5 in DX mode: 0.48
Effective size of D810 in DX mode: 0.47
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SethG
Senior Member
Seth.... when people speak about reach, they generally mean angle of view.... and not "cropping ability." I think you are confusing the issue when you drag crop ability into this.
Fact is.... when you put a 50mm FX lens on a DX body you get a much narrower view than it it was on an FX body.
Once you include cropping ability, then you can say the Sony A7R II has "more reach" than a Sony A7S II..... because you "can crop more." We all realize this because even though they are both full frame cameras with full frame lenses, the A7R II provides greater resolution with a 42 MP sensor rather than the 12 MP sensor in the A7 SII.
But that wasn't what the OP was referring to. He was asking what the general definition of "reach" was when comparing DX and FX.
O
OlyPent
Guest
If Nikon released a 30mp DX, it would have more resolution with any given lens than the D810. The D810 would just have a wider field of view with that lens and since most people crop wildlife (for example) shots, the DX camera would be the better choice. Provided other things (like a high ISO setting) didn't interfere with the final result.
Hi James, It's more than just "pixel math" (i.e. "more pixels on the bird") as crop sensor cameras are more demanding of lenses and also carry an "aperture penalty" (As Thom Hogan calls it). If you look at just "# of pixels on the bird" and extrapolate that concept to a micro 4/3 camera with the same megapixels, it has more pixels on the bird but it doesn't result in better image quality. Or go even further with the point and shoot size sensors, etc.
Here are some good DPreview sources for information on how APSC is more demanding of lenses and also about the aperture penalty. You can also look at DXOmark sharpness scores between APSC and FF cameras using the same lenses. According to DXO only a very few lenses will achieve near the maximum potential of the sensor when used on both APSC and FF (I recall them using one of the Zeiss lenses as an example but I don't remember which one -It showed nearly identical scores for a APSC and FF camera of the same Megapixels).
Read especially page 2 about aperture penalty ("equivalent aperture"):
https://www.dpreview.com/articles/2666934640/what-is-equivalence-and-why-should-i-care/2
Discussion on Crop sensors being more demanding of lenses read especially page 3:
https://www.dpreview.com/forums/thread/3968507?page=3
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James809
Senior Member
3+ pages of responses should give you an indication.
James809
Senior Member
What?!?!
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