1.5 x the focal length on a Non DX lense with DSLR body !?

The sensors for most digicams are very small such that a normal lens is more like 10mm. Therefore, instead of a 1.5x "crop factor," we are talking about 5x and a 50mm is almost a super tele. It is probably not long enough for a small bird, but it would be like a 250mm lens for 35mm film.

Go over to the Mi*** forum. They will tell you how to take Moon pictures with simple binoculars (and with super high resolution enough to make mural sized prints)!

 

Those guys have been around and beating their mini drums for decades now. Never did they make any mistakes about the focal lengths!

 

Vivek.

All,

 

It has nothing to do with the recording medium, whether it is film or a sensor.

 

This statement is not accurate even if you apply it to DSLRs only.(Let's compare apple to apple so as speak)

 

let say Nikon release a full frame DSLR (let say it has the same pixel density as the current D70, pixel per unit area in the sensor)

 

one pround owner of this new body put a 450 mm telephoto on it and took picture of some bird and he is overwhelm with the result, here come his mate, owner of a D70 with a 300 mm and say, "I can achieve the same result with a 300 mm on my D70", because he believed what the salemen has told him, "you can change focal length with a D70", he took the same picture of the bird and they compare their pictures on a 21 inches monitor (guess who own the monitor). The D70 owner while he is poorer, but a honest person and said, My picture look softer compare to your, why !? Why !?

Let me try my 300 mm on your body, they compare result again on the 21 inches monitor, the pictures now have the same sharpness & quality, except, you guessed, the bird is half the size !!!!

 

So a 300 mm lense is a 300 mm, it is not a 450 mm !!!

Need I say more, to believe otherwise is self fulliling.

Robert -

 

You'd have to shoot it yourself to convince yourself of all the ins and outs. The "the 1.5x crop/multiplier" (no holy wars, please) gets a little complicated, but in the specific area of "shooting small birds at a distance", it's almost like a free lunch.

 

If you care, this is from a guy who has not made the jump to (DSLR) digital yet, but I have a few thousand frames on borrowed cameras.

Todd, There is nothing as a free lunch !! You should know that.

Short cuts, short cuts... They are all short cuts !!!

Cropping ratio, closeup lenses, teleconverters......

They all try to immitate the real thing, but they are not.

I would not go as far as saying, " Selling chicken shit as carviar!!!"

But you know what I mean.

I wonder what the difference is between this thread and the one posted by (immediately deleted but this one keeps going on comparing the merits of chicken crap and fish eggs) Leslie Cheung!

 

Vivek.

Vivek,

 

Under the colourful language, there is a serious message !!

The message is to explode the truth and expel the myth about the 1.5X claim. I am not sure about you, But I myself certainly learn a few new thing from others in this thread about lense & DSLR body.

 

You "sound" like a serious person, But are you serious enough to accept the truth !!! My friend.

 

In my humble opinion, the contribution by all thus far has been great in helping someone new to DSLR to make a concious decision about the choice he/she will make on DSLR.

Robert,

 

I use a 6x6/6x4.5 (Rollei SL66), Olympus pen F/T ("half frame"), 35mm (Nikon F2 and several others), LF (4x5, 5x7 for macros).

 

Many lenses I use (mostly for macros) are used in all the systems.

 

It is not very difficult to understand what happens with the 1.5 crop factor.

 

Let the PR people say whatever about the 1.5X, etc. This topic has been discussed to death in many forums of photo.net.

 

If you feel that Nikon is deliberately misleading people about this 1.5X issue, say it so.

 

Yes, I have/use a D70 as well. If I were you, I would rather worry about the fabulous view finder and the AF system that D70 offers than the crop factor!

 

Vivek.

This is all academic since there is no full-frame sensor which matches the pixel density of the D70 and if there were, it would cost in the ball-park of $15000-$20000 so why compare to something that does not exist. The fact is the small-sensor DSLRs that are on the market have higher pixel densities and it's likely to remain so for the foreseeable future.

The 14MP Kodak DSLRs have pretty much the same pixel denity as the D100 and D70. There may be a bit of round off difference, but for all practical purposes, the density is the same, or at least close enough. Canon's EOS 1Ds has a lower pixel density than the 6MP Nikons.

 

Kodak: 4500 X 3000 pixels over 24mm X 36mm = 15625 pixels/square mm

 

Nikon: 3000 X 2000 pixels over 23.7 X 15.6 = 16228 pixels/square mm

The Kodak lacks an antialias filter and has problems with colour fringing and noise at high sensitivity settings so it doesn't make a very good example. I would bet that the D70 produces better image quality than the 14 MP Kodak when cropped to the same FOV and especially if a high sensitivity is needed. What I'm trying to say is that the APS size sensors are likely to retain an advantage in pixel density over a longer time period. (The 20D has 8 MP in a 1.6x sensor)

 

A 450 mm f/2.8 lens is actually quite a bit more expensive than a 300/2.8, not to mention heavier. A DX format DSLR is a good way to add a little reach to your shots if you can't afford or handle an enormous lens. Of course, there are other problems in VF size and wide angles but that's a different issue.

<i>Do you experience similar confusion when you go digital !? </i>

<p><p>

Not until I read this thread... :-)

<p><p>

<i>It is all losses and no gain !!!!! </i>

<p><p>

<b>D70 + 600mm + 1.4 TC</b> at a wildlife preserve. I would call that a gain.

<p><p>

The Kodak full frame camera has a removable anti aliasing filter and it can be changed.

 

If D2X does not show up soon, I am going for the Kodak camera.

 

Vivek.

If pixel density is the only variable, then-

 

It would appear in theory, it may be possible that different focal length can be effectively achieved by the use of cropping ratio IF (This is a big IF) : the pixel density in the image projected area is proportionally changed to accomodate the increase/decrease in cropping ratio, and the neccessary software to drive it.

 

i.e Instead of mounting different lens, you slip in different size of sensors with different pixel density to get the require focal length !? It would be good, would it not !? Instead of carrying a 20 Kgs 450 mm telephoto, one carry a 2 gms sensor !!!

 

However, this would not stop one to use the 450mm on a higher density "slip on" sensor to achieve even better result.

 

In film photography, to some degree this is already possible !!! i.e Different film speed & Format (Negative size)

 

Food for thought !!!!

"The "the 1.5x crop/multiplier" (no holy wars, please) gets a little complicated, but in the specific area of "shooting small birds at a distance", it's almost like a free lunch"

 

I shoot birds with D70 (small sensor) and N80 (full size 35 film), using the same lens (300/4). In either case nearly the same size of the bird is showing in both viewfinders, with slight variation caused only by the optics of the viewfinder itself. Angle of view is wider on N80, but I cannot observe expected by some people magnification (1.5X) of the bird in the D70 viewfinder, it is just not there. Of course quality of viewfiders and magnification of the viewfinder optics itself is different. I would like to get a free lunch here, but how?

 

I guess the only free lunch is that I see narrower field of view and can concentrate better on the bird.

When the 1/2 frame Pen F was popular; some folks used their full frame 35mm slr lenses. They were NEVER as confused about angular coverage and focal length; like todays discussions like this thread. Maybe math has gone down hill; or the usage of a slide rule made folks think clearer back then. Learn to think angular coverage; for a film/sensor and lens combo. This is what the film industry does. The lens doent know what the heck sensor it shines on. It might be a vast range of sizes. Using angular coverage cuts thru the crap; and makes a common ground.

It's all about acceptable image quality, if a lesser-design or less-expensive set-up achieve the kind of quality that you want in your field, well & good, nothing wrong with that. Beside equipment is only account for a small percentage in achieving a powerful picture.

 

But I must call a spade a spade and an ace an ace !!!

A 50mm Nikon F nikkor can be affitted to a Nikon F; Dslr; a video camera with a C mount adapte; a 16mm movie camera with a C mount adapter; an 8mm movie camera; with an additional C to D adapter. <BR><BR>IN ALL cases; the lens is still a 50mm focal lengths lens. <BR><BR>The smaller formats have a smaller angular coverage. <BR><BR>Figure the angular coverage using the films half dimensions; divide by the focal length; then use inverse tangent to give the half angle.

Sorry, the last sentence should read,

 

But WE must call a spade a spade and an ace an ace !!!

In film making; the American Cinematographers Manual list tables of angular coverage; for a mess of film/sensor sizes versus lens focal lengths. This reduces the confusion of which lens to use or rent. The tables are in horizontal and vertical degrees. One can make your own cheat sheets; for your combinations; and place them on cards; and then burn them into your brain.

Frank, Kelly

 

Someone tried again to confuse the issue with pixel density & overall picture quality. I am just trying to demonstrate with an example that even that argument doent stand up.

Vivek, the Kodak 14 MP 24x36 mm DSLR certainly doesn't have an antialiasing filter, removeable or not. Their medium format back did have a removeable AA filter but it's out of production like so many things that were too good to be true. :-)

Ilkka,

 

Thanks! I will check again with a source who informed me on this. He has a Phase I so, knows what he is talking about.

 

Anyway there appears to be some USE for this redundant thread for those who are not confused about 1.5X whatever.

 

Vivek.

one of the many reasons i'm not going digital.

 

ironically, none of them are a bias against the medium. just can't find a digital camera i like.