How to achieve normal perspective on 1.6 DSLR?

I am confused by this. On a 35mm sensor the 50mm is considered "normal"... because the eye is approximately 50mm deep?

What lens would give a "normal" perspective on the Rebel sized sensor?

Would a 50 mm lens give a normal perspective, just cropped?
Or do I need a 50/1.6= 31.25 mm lens to get normal perspective?
Or something else?

Please advise.

i'm not sure if you'll find a 31.25mm lens, or a 30mm lens for that matter. 28mm is pretty darn close though.

this is unfounded, but i recall hearing that a "normal" lens is a lens which has a focal length equal to the diagonal of the film frame.

as such, for 35mm full-frame, the film frame is 24x36 mm so normal lens then is:

square rt of (24^2+36^2) - hypotenuse of a right triangle with sides of 24 & 36 mm = 43.26... mm

for 4x5 camera that would be roughly 64mm lens. for 6x6 (2.25"x2.25") it would be 84mm lens.

hense you get the 50mm, 65mm and 80mm lenses.

using the same methodics i would assume that a APS sized chip on canon's cams would be as follows (calculated for 10D) 22.7 x 15.1mm size chip, hence "normal" lens would be a tiny bit over 27mm. 43/1.6=26mm - close enough.

I suppose you can set your kit lens, if you got it, to 31.25 mm, approximately.

The confusion is the angle of degree. If you have a 100 mm lens on a 35 mm camera and put it on adsdalr with a 1.6 factor the angle of degree would be the same as a 160mm lens on a 35mm camera.

In my opinion when n the say you have the same asw if you put a 160mm tele on it, I disagree. The lens does not give you anymore pulling power as if it were on a 35mm camera but its appearence in crop factor gives you that effect. An example is if you took a photo with a 400mm lens of a heron on a 20D it would fill the sensor up but on a 35 mm it would on fill about 2/3 thus giving the apperaence that it has greater magnification. But in fact 400mm is 400 mm, in opinion.

fact or opinion?

the truth is 400mm is indeed 400mm.

the "normal" lens for a 1.6x DSLR would be a 28mm or 35mm. canon makes a couple models of each of these.

Yeah, relative to 35mm frame, it's a 400mm lens...

But then... 35mm frame was taken pretty much randomly. Right? It could've been "30mm" or "40 mm format" as standard.

Then, with 30 mm format, the lens would've been around 450mm...

Then... if we take an 80 mm hasselblad medium format lens and put a 35mm film behind it. What does the lens become?

Are you sure that none of these threads can answer your question?

-=CROP FACTOR=- 10,000 posts on the X-Factor

DOH... At least it's the right forum

Sorry CDS... nobody gives a definite answer.

I am confused... yet again.

I am not concerned about the image quality.
I don't care what you call the "crop factor"

I am concerned about:
1) Angle of view
2) Depth of field

Now. On 35mm film you get certain angle and certain DOF with 50mm f/1.4

Question: What focal length and what aperture do you need to get the same image in Drebel sensor???

Some guy quotes:

He divides the film focal length and aperture by 1.6...

So... is this a huge limitation of the small sensors using 35mm lenses? Does it mean that equivalent picture on 1.6 sensor can be achieved with only:
31.25mm f/0.875 lens?

If so, all small sensor cameras are fundamentally flawed when using the 35mm format lens?

It would mean that even the most expensive glass, like 24L and 35L translate to mediocre equivalents of 35mm because of DOF restraints they produce:
24L = 38.4mm f/2.24
35L = 56 mm f/2.24

The aperture stays the same, but we are getting depth of field similar to slow lenses!

If we take "usual" lenses, the equivalen DOF can be too big!
28 f/2.8 which translates into a "normal" 44.8mm lens would on a 1.6 sensor produce a picture with a depth of field which is equivalent to 44.8mm f/4.5 lens on 35mm film!

Now... you're still getting the same amount of light, and it keeps your shutter speed the same. But what you're losing with 1.6 size sensor is small DOF of 35mm film.

Makes sense?

The quote is from Rayz at the bottom of the page.

https://photography-on-the.net/forum/showthre​ad.php?t=40821

CDS: I am stirring this because I did not see anybody post about the DOF issue on the smaller sensors.

Is would mean that while f stops are the same, it's impossible to get as small DOF as we would with full frame sensors.

Or am I wrong?

There is allways alot of confusion on this issue.
A 'normal' lens has nothing to do with either focal length nor angle of view.It's got everything to do with magnification
Approx 30mm is normal on a 1.6 crop DSLR.But don't expect to open your spare eye when looking though the viewfinder and see the same sized image because viewfinders have magnifications of thier own

ok, what about DOF? do you need aperture 1.6 times faster to get the same DOF?

The longer the focal length of a lens the flatter the perspective, assuming framing the subject identically. This is irrespective of sensor size. So, a 28mm lens will show a greater perspective than a 50mm. This is not the same as FOV.

You can try it yourself with two or three objects spaced front to back on a table, using three different focal lengths frame the front one the same and see the effect on the other two.

This is precisely why Canon makes an EF 28mm f1.8 lens...

Have Fun,