definition/usage of 'reach' ?

[chris clements]

In another thread I was pulled-up over my use of the word 'reach', which I have always taken to be just a shorthand we'd coined here to use in APS-FF AoV /focal length explanations - a word that was both clear to newbies and not too offensive to our 'strict definitions' wing.
My corrector (below) states that 'reach' also encompasses pixel density - a connection I have never made when I have used the word here, or seen made by others using it.

What is everybody elses' understanding of the word as we use it in these forums?


" Actually you are wrong. Reach comes from pixel density, not sensor size. Reach is about maximizing resolution regardless of distance and given the same lens....
The 1Ds Mark II has more reach than the 5D or the 1D Mk II, even though it is full-frame and its sensor is bigger than the 1D Mk II."

[SkipD]

In my opinion, pixel density should not be used as a part of the definition for the term "reach". That's because the term is used for film photography as well as for digital photography. The term has been around a lot longer than digital cameras have.

That said, the other poster did make some valid points about the differences between various digital cameras and their capabilities.

[Jon, The Elder]

I've always used it in connection with or instead of 'range', in regards to lens focal length abilities.

Pixel peepers are in a different world of describing things sometimes.

[Mark_Cohran]

In my opinion, pixel density should not be used as a part of the definition for the term "reach". That's because the term is used for film photography as well as for digital photography. The term has been around a lot longer than digital cameras have...

I've always used it in connection with or instead of 'range', in regards to lens focal length abilities.

Pixel peepers are in a different world of describing things sometimes.

Pixel density has nothing to do with the "reach" of a lens. That's totally a function of the lens focal length and the sensor crop.

Of course, there are those that attempt to over-complicate everything. A simple thumbrule, for them, has to be dissected and its component parts analyzed ad nauseum until they convince others that the guideline is worthless and the only correct way to do things is to measurebate, test, and measurbate some more. They suffer from analysis paralysis. Never mind that great photographers have been using those thumbrules for years to capture outstanding images.

For some reason, the digital age has brought out a swarm of shooters whose passion seems to be analysis and argument. They shoot rulers, charts and batteries instead of landscapes, nature and people. And then they wonder why others don't care for their photography.

Okay, rant over. I didn't know what I was going to say when I started writing, but I feel better now. :)

Mark

[treeshugger]

Unless I'm mistaken, higher sensor density would allow more cropping post processing which would have the same effect as a longer lens or a camera crop factor. Its obvioust that "reach" has something to do with angle of view, whether it is what is seen in the viewfinder or what can be achieved after cropping. Perhaps a good definition would be narrowness of angle of view while still achieving good detail?

[AJSJones]

[geezer diatribe]
In the days when film was film, resolution was measured by the quality of the film not its total area; i.e. the ability to resolve (duh!) fine details. In those days you used lenses to make the image bigger to be able to make a bigger and better print of, say, the distant bird. The bigger the image falling on the film, the greater reach the lens had.
Then came digital. Resolution now means how many pixels (to most people it seems) regardless of the size of the pixels or the fineness of the details they can resolve. In an APS-C sensor on a D30 with 3MP and a similar size sensor in a 400D at 10MP, which one is going to provide the bigger picture of the bird in a print?
Treeshrugger has the right idea about the way reach should be expressed in a digital era : number of pixels per angle of view. The bigger the number, the bigger the reach. Narrower angle of view or more pixels for the same angle will create a more detailed image (as long as the pixels are good enough quality). Reach is one of those words whose meaning has changed with digital, whether we like it or not. [/geezer diatribe]

[Jon, The Elder]

Reach is one of those words whose meaning has changed with digital, whether we like it or not.

Sorry, can't go along with that.

If I am shooting across a horse arena and can't fill the frame with subject matter using my 28/135, I swap it for my 70/200 which gives me greater reach. I can't see how this differs between film and digital. It is a matter of optics "I need a lens with greater reach" is a common enough term among shooters past and present.

Sensor size, pixel numbers and density are all after the fact of gaining reach.

[AJSJones]

Sorry, can't go along with that.

Sensor size, pixel numbers and density are all after the fact of gaining reach.

Do you ever print your images "after the fact" of acquiring them ;) ? Is the quality of the print limited by the number of pixels in what you want to print? If everyone used the same density of pixels, I would agree that lens determines "reach".

"I can't reach it" is a sentiment that, to me, implies a limit. My point was that in the digital era, once you've got to the limit of your lenses, you can improve "reach" by increasing the pixel density of the camera you choose to use (for my 500mm lens, the 20D has much more "reach" than my D30 - even though what I see in the viewfinder isn't much different).

[hidden forms]

[quote=Jon, The Elder;2773826]Sorry, can't go along with that.

If I am shooting across a horse arena and can't fill the frame with subject matter using my 28/135, I swap it for my 70/200 which gives me greater reach. I can't see how this differs between film and digital. It is a matter of optics "I need a lens with greater reach" is a common enough term among shooters past and present.

Right to the point, thats what i understand it meant, with what ever camera your using, you are trying to capture an image, if you can't fill the frame with what your trying to capture you swap for a larger lens for more reach

[Hermeto]

Just like Optical and Digital zoom in camcorders: both of them represent the 'reach’ of the lens..

[Jon, The Elder]

NOT digital zoom. That is a byproduct of in camera manipulation once maximum optical zoom is achieved. One of the oldest ploys used by camera manufacturers to impress P&S noobies with the old 10x zoom (digital). All in all a misleading and damned dirty trick on gullible first time buyers.

But it seems, still believed by some.

[AJSJones]

Right to the point, thats what i understand it meant, with what ever camera your using, you are trying to capture an image, if you can't fill the frame with what your trying to capture you swap for a larger lens for more reach

Then you could capture a better image by swapping for a camera with a sensor with more pixels . Couldn't do that with film so the issue never arose as to whether anything else affected "reach". Some used to think that a smaller sensor yielded more reach but it's actually the pixels that matter...

[Hermeto]

Jon, what ASJones said about reach:
… once you've got to the limit of your lenses, you can improve "reach" by increasing the pixel density of the camera you choose to use …

is basically the same as what you said for digital zoom:

… camera manipulation once maximum optical zoom is achieved...

Is it not?

This is how I understand this whole thing, in layman's terms and broken English..

- When you zoom in with dSLR, you do it with the lens - until you fill the frame, or actually, sensor.
Let's call it maximum Optical Reach.

Then, in post processing, you can further enlarge that same image from the sensor - until you fill the frame of the final picture (digital or printed).
Higher pixel density will allow higher magnification (while preserving decent resolution).
That is the Digital Reach.

- When you zoom in with P&S/camcorder, you first use optical zoom, and when its reach is maxed, you continue zooming in with digital.
If you're careful, you can achieve decent resolution for your picture/movie.

If you look at the digital camera + lens + post processing (in camera or with the computer) as a System, AJSJones' explanation makes sense.

[Permagrin]

reach and resolving are not one in the same and should not be confused.

Reach is a distance term and often interchanged with RANGE...both are measured in distance...and in present case, have to do with lens mm..

Resolving power of the sensor: the ability of an optical instrument or type of film to separate or distinguish small or closely adjacent images. • the ability of an electronic device to produce images that can be distinguished.

Cropping down has to do with resolving. Distance from a subject that is captured by the lens is reach.

[Hermeto]

Hmm, relationship between distance from the subject and image on the sensor has to do with lens resolving power too..

[20droger]

Then you could capture a better image by swapping for a camera with a sensor with more pixels . Couldn't do that with film so the issue never arose as to whether anything else affected "reach". Some used to think that a smaller sensor yielded more reach but it's actually the pixels that matter...
Yes, you could.

In film, the equivalent of pixel density is "grain." Any film person can tell you the difference in image quality between an ASA 32 and an ASA 400 film. A fine-grained film (i.e., low-ASA film) was generally capable of much greater enlargement without loss of detail.

The parallel between gain and pixel density breaks down, however, when one realizes that the ISO of a digital camera is only roughly equivalent to the ASA (ISO) of film. With film, a higher ASA almost invariable meant a greater sensitivity to light and a coarser grain. With digital, a higher ISO means a greater sensitivity to light at the same pixel density, but with an accompanying increase in noise.

The issue become even more complex when you also realize that an increase in pixel density produces a finer resolution, but only if the same kind of pixels are used and the same per pixel digitizing process is used. These differences are why a 1Ds Mark II produces higher resolution pictures than a 30D, even though the 30D technically has a slightly higher pixel density (more pixels per millimeter). Each single 1Ds Mark II pixel is superior to each single 30D pixel (has a better gradient curve), and the pixel digitization is also superior.

But then, you should get something for the extra 1DS Mark II bucks!

[AJSJones]

reach and resolving are not one in the same and should not be confused.

Reach is a distance term and often interchanged with RANGE...both are measured in distance...and in present case, have to do with lens mm..

Resolving power of the sensor: the ability of an optical instrument or type of film to separate or distinguish small or closely adjacent images. • the ability of an electronic device to produce images that can be distinguished.

Cropping down has to do with resolving. Distance from a subject that is captured by the lens is reach.

The definition of resolution you present is one of two currently in common usage and is the older of the two (the newer one referring simply to the total number of details that can be captured , as in "a 22MP camera has more resolution than a 10MP camera" - to quote Safire, with respect to usage "When enough of them are wrong, they're right" :) ) A new definition emerged because of the entry into the digital era even before digital cameras became affordable : 640 x480 is a low resolution monitor, while 1920x1200 is a high resolution monitor. I don't like the addition of a new meaning because it leads to ambiguity in these kinds of discussions :) - but there apparently wasn't a better alternative available.

I make the assumption that a photographer's goal is to view the captured image either on screen or in a print. For a printer, we would like to have enough information to create a "good" print. That is why we use various lenses, each suited to its task and not a single fixed wide-angle lens and crop down from there to the desired image, right? Thus matching the desired image size to the size of the capture medium - framing - so as not to waste the medium or degrade the quality of the capture.

Increasing "reach" used to mean using a longer FL lens, and it can still be used that way. It can be used in a new way too: I love my D30, its colors and nice big low-noise pixels. However,when I use my 500mm lens, sometimes the birds are too small in the VF to produce a nice print, so I can almost double my "reach" by putting on a 400D body - the acquired image is almost twice as many pixels high as with the D30 body and I can now make an 8x12 instead of a 4x6 print at 300ppi. Just as on the same 400D, if I take off a 200mm lens and put on a 400mm lens I double my reach. It can be done either way.

Just for clarity, I interpret "digital zoom" to mean interpolation and creation of new pixels that weren't there before and that is not increasing reach (it's just enlarging more) - that is a totally different issues from my point above which uses more real pixels to capture the same optical image. So coming from my D30 and a bird image that is 250 pixels high, I can get a 500 pixel image by either putting on a longer lens or by using a better body with the same lens.

Andy

[AJSJones]

20dRoger
Agreed there are differences between pixels even at ostensibly the same "spacing". The elctronics, microlenses, amplifiers, max # of electrons etc.. In the discussion of "reach", I see these as secondary just as different 500mm lenses have different CA , contrast, flare etc. They all matter in the end - waiting patiently for a 1DsIII :)

[superdiver]

I associated reach with my dads ability to hit me from anywahere in the car. Thus it means "range" to me....never even heard it associated with pixels...

[AJSJones]

I resolve not to clobber you with my 500 mm lens if you come within reach :)

[superdiver]

LOL

[Jon, The Elder]

AJSJones and I are saying the same basic thing....

A new definition emerged because of the entry into the digital era even before digital cameras became affordable : 640 x480 is a low resolution monitor, while 1920x1200 is a high resolution monitor. I don't like the addition of a new meaning because it leads to ambiguity in these kinds of discussions

My comments are taken from the "capturing" the image stage and not beyond into post processing. Few people do their PP in the field, and so I consider the reference to 'range' when I actually am shooting. Not after the fact.

Once PP is in the workflow, the above quote holds as true.

[20droger]

20dRoger
Agreed there are differences between pixels even at ostensibly the same "spacing". The elctronics, microlenses, amplifiers, max # of electrons etc.. In the discussion of "reach", I see these as secondary just as different 500mm lenses have different CA , contrast, flare etc. They all matter in the end - waiting patiently for a 1DsIII :)
I'd be happy with a $750 40D!

Yeah, right! Like that's gonna happen before the 50D comes out.