"Multiplier" on digital (D100)

[waldenl]

Can someone clarify something for me. On a digital camera (in my

case a D100, but question holds on any) I know there is

the "multiplier" effect. In my case it's roughly 1.5. So my 50mm is

a 75mm w/o a loss of light. However, what does that 75mm mean? Do I

have the magnification of a 75mm, or just the narrower range of

view?

 

To put it another way, can I get as "close" to a far away object

with my 300mm on my D100 as with a 450mm on a F100?

 

Thanks,

-Walden

[mark cohran]

You have a "crop" of a 50mm shot that will give you the same field of view as

a 75mm lens. The perspective and DOF are that of a 50mm lens, however, in

the camera viewfinder you will perceive the scene as being magnified, but in

this case perception is not reality.

 

To answer you last question - it will seem that you will get as close with a

300mm as you can with a 450mm, but you will still have the optical

characteristics of a 300mm lens.

[kelly_flanigan1]

Your lens still has a 50mm focal length. The digital sensor is smaller than the 24x36mm normal film size for 35mm. With the smaller sensor; a 50mm lens on your digital camera will be covering less angle; since the digital sensor is smaller than 24x36mm. This means that your 50mm lens on your digital camera "acts" like a 75mm lens; on a regular film camera; <b>in angular coverage</b>. Imagine cropping your film camera shots done with your 50mm lens; and throwing away the stuff at the sides and top and bottom away.

[kelly_flanigan1]

This concept also happens with film and movie cameras too; in which a 50mm Nikkor can be placed on a full frame 24x36mm Nikon F; a half frame 18x24mm camera; a 16mm movie camera; a video camera; and a regular 8 movie camera. Each camera has a smaller sensor/film aperture size; and the angular coverage is less. The lens is still a 50mm lens in focal length. In movie cameras; a normal lens is considered to be "normal" when roughly twice the focal length of the film diagonal.

[peter_foiles2]

This whole question is much easier to understand if proper terminology is used. dSLR such as the D100 do not have a "multiplier" effect. They have a "crop factor". In your example of the 50mm lens you are effectively cropping the frame to have the same angle of view as a 75mm. NOTHING else has changed.

[waldenl]

Thanks all, that's what I thought. Peter, you're correct that would clarify things, of course the marketing department might not like it as much <G>

[kelly_flanigan1]

The "multiplier" effect term was used by marketing in the 1960's; in explaining how full frame slr camera lenses; "acted" on 1/2 frame cameras; such as the Olympus Pen F. My neighbor used Exakta slr lenses; on his 16mm movie camera; in the 1950's and 1960's; as "super telephotos". This is when I first heard the term "multiplier" effect. Marketing has thus used this term almost 1/2 century.

[jespdj]

Your question is a frequently asked question; by searching the forums you'd have found an explanation quickly. Here are a few links:

<p><a href="http://www.luminous-landscape.com/tutorials/understanding-series/dslr-mag.shtml">Understanding the DSLR Magnification Factor</a><br>

<a href="http://www.photo.net/learn/optics/dofdigital/">Depth of Field and the Digital Domain</a>

[walter_degroot]

i am hoping , that, in the future, digital slr's will have a larger ( 24 x 36 mm) sensor. as far as i know the only one is the kodak. nikon 12,3? megapixel camera. there is likely a high degree of interchangability if not full functionality with other Nikon slr's

as things progress, it's likely others will make and sell cameras with larger sensors.

the main drawback/problem is that a wide angle lens must be used to get a NORMAL field of view. indoors, we have to un-naturally squeeze people together to " get them all in" *** OR back up to the wall.

**with a film camera a 35/28/21 mm lens isn't so hard to come by.

with a slr digicam a 35mm is close to normal field of view and a 35mm is harder and more expansive to make, when there is a mirror behind it as in a film slr or one that takes the same lenses.

the back focus area/distance is 45mm or so and a 35mm lens or

wider ( shorter) has to be an "inverted telephoto" or "retrofocus " design. easier for all and cheaper if th sensor was larger and " normal" as in film camera rulles and methods applied.

How many of us can afford $6.000.00 for the kodak/nikon plus big bucks for lenses? only a few!

that's why we got a much smaller digicam with an electronic VF and a lcd screen. when we look tru the vf it zooms the whole thing weighs 6-8 ounces.

i recall toting 2-3 slr bodies and several lenses and batteries, what a load! heavier than my 4 x 5 (wooden)( hollow) speed graphic!

do i really want to carry all that again?

[david arnold eugene, oreg]

The 11 mpxl Canon 1D's also has a full-size 24 x 36 mm sensor.

[steven_clark]

The perspective of a "75mm" crop of a 50mm lens is exactly the same as a 75mm lens at that distance. The only change to any of the features should be the DOF as that is determined by absolute rather than relative aperture.

[tim_cronin]

I believe the following illustrates the "multiplier" effect. Imagine:

<p>

1) From the same 35mm negative<br>

2) Make a 9"x6" print<br>

3) Make a 6"x4" print<br>

4) Place the 6x4 on top of the 9x6 in the centre<br>

5) Cut around the 6x4 print<br>

6) Throw away the bits you've cut off<br>

<p>

You now have two 6x4 prints that illustrate the relative "multiplier" effect<br>of a digital sensor vs 35mm film using the same lens.