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'Normal' lens for a dslr

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Marwood

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I'm just about to buy myself my first dslr. Part of my reasoning for this is because it's virtually impossible to get a limited depth-of-field effect with my existing, built-in-lens camera.

I had great fun playing with a 35mm SLR using a fast 50mm prime and was after the same sort of thing.

However, do I buy myself the 50mm f1.8 or a 35mm f2?

I've heard everyone rave about what a bargain the 50mm is. It's not quite such a bargain in the UK (It's priced at £99, making it nearly twice as expensive as in the US, based on current exchange rates), but is still pretty cheap.

The 35mm would give me a field of view equivalent to a conventional 35mm film + 50mm prime set-up, though.

So my two questions are:

Why was a 50mm prime the stock lens for much film photography? If it was because it gave a useful field of view, then the 35mm f2 lens will be more useful, won't it?

Would I be right in saying the shorter focal length of the 35mm lens (and the slightly less open apperture), mean that I won't get quite such a promounced depth of field effect as on the 50mm lens, assuming the subject to be the same distance from me? In which case, would paying more than twice as much money to buy the 35mm f2D mean I actually sacrifice some of the pronounced depth of field effect that I'm buying a dslr for?
 
Marwood said:
Why was a 50mm prime the stock lens for much film photography?
Click to expand...
The 50mm was easy to produce, small and cheap. It was/is
the Honda Civic of photography. Not great by any means but
consistently, slightly, above average. And, did I mention?, cheap.
Marwood said:
If it was because it gave a useful field of view,
Click to expand...
I never found 50mm on film especially useful.

Matt
 
i don't think the difference in depth of field between f1.8 and f2 would be very much. I have also been looking at those two lenses because i wanted a fast "normal" prime. the 50 will more of a short tel but will be good for portraits and the 35 is closer to a "normal" lens.

i still haven't decided.
 
I didn't expect the slightly smaller maximum aperture to have that much effect but, when combined with a shorter focal length, doesn't this mean it'll give up some of the dpeth of field effect that would be available with the 50mm?

If I used a 50mm lens on a film slr, then took it across to the dslr, I'd lose a little control over depth of field because more of the out-of-focus are will fall outside the sensor.

A 35mm lens would correct ofr this but twould then lose depth of field because it's a shorter focal length. Is that right?

If the 50mm was popular because of cost, not because it was a particularly useful focal length, then it still make as much sense to buy a 50mm prime for a dslr (after all, they're still cheap).

In which case, there's no logic to me buying a 50mm equivalent (35mm) lens to get the same field of view, because there's no great reason to aim for that field of view? Instead I should get the cheap lens and the greater depth of field control it offers?
 
The DOF difference between the two is not so significant, both with be dramatically better than your current camera.

more important is the field of view. Both are great, on operates at 52mm and the other at 75mm on a dslr. If you have a zoom right now or can borrow one, keep it 52mm for a day and then 75mm for a day and which you prefer.

I went for the 35mm, but then I added the 85/1.8, skiping the 50mm.
 
That's the sort of thing I was hoping to know.

The 35mm f2 was my first choice, but the 50mm is less than half the price.

Since depth of field is one of the major reasons for me moving from prosumer to dslr, I didn't want to do anything to reduce that control over depth of field.

Either way, should be better than the 5.7mm focal length of my current camera.
 
Unless you buy a DSLR with a "full-frame" sensor the DOF will be slightly larger than what you would get from a film SLR, since the imaging plane is smaller. Having said that you can still get very shallow DOF... much shallower than what you're getting now.

At the same level of magnification (same framing in other words), and the same aperture the 35mm f/2 and the 50mm f/1.8 will both give the same DOF. So (with the exception of the f/1.8 aperture) you're not really losing DOF by going with the 35mm although the narrower field of view of the 50mm does make it easier to isolate the subject by cutting out some of the background. I find the 50mm very good for upper body or head/shoulders portraits, but for general walk-around use you often can't back up far enough with it to get everything into the shot.

The 35mm f/2 is the nearest you'll get to a 50mm on film in terms of field of view, but technically a "Normal" lens is one whose focal length is equal to the diagonal of the imaging plane... that's 42mm on film, and 28mm on a DSLR. For this reason some people use a 28mm lens, or the Sigma 30mm f/1.4 as a normal lens instead.
Marwood said:
That's the sort of thing I was hoping to know.

The 35mm f2 was my first choice, but the 50mm is less than half the
price.

Since depth of field is one of the major reasons for me moving from
prosumer to dslr, I didn't want to do anything to reduce that
control over depth of field.

Either way, should be better than the 5.7mm focal length of my
current camera.
Click to expand...
 
Because the 50mm focal length is closest to human eye perspective.. (someone correct me if I am wrong!)
Marwood said:
I'm just about to buy myself my first dslr. Part of my reasoning
for this is because it's virtually impossible to get a limited
depth-of-field effect with my existing, built-in-lens camera.

I had great fun playing with a 35mm SLR using a fast 50mm prime and
was after the same sort of thing.

However, do I buy myself the 50mm f1.8 or a 35mm f2?

I've heard everyone rave about what a bargain the 50mm is. It's not
quite such a bargain in the UK (It's priced at £99, making it
nearly twice as expensive as in the US, based on current exchange
rates), but is still pretty cheap.

The 35mm would give me a field of view equivalent to a conventional
35mm film + 50mm prime set-up, though.

So my two questions are:
Why was a 50mm prime the stock lens for much film photography? If
it was because it gave a useful field of view, then the 35mm f2
lens will be more useful, won't it?

Would I be right in saying the shorter focal length of the 35mm
lens (and the slightly less open apperture), mean that I won't get
quite such a promounced depth of field effect as on the 50mm lens,
assuming the subject to be the same distance from me? In which
case, would paying more than twice as much money to buy the 35mm
f2D mean I actually sacrifice some of the pronounced depth of field
effect that I'm buying a dslr for?
Click to expand...
--
'Procrastinate now, don't put it off.'

 
Pradipta Dutta explained this earlier to me in this forum:

"By definition, normal perspective is provided by the focal length that is equal to the length of the diagonal of the film or the sensor. And if you do the math, for a DX sized sensor with roughly 16x24mm dimensions, the normal lens would come out to be the 28mm lens.

By the same token, the 45mm is considered the prime that provides closes to normal vision on a film SLR."

--------
Koen A.
 
That would make a lot of sense.

Thanks everyone.

Hmm, several things to think about there.
 
Having had both the 50mm f1.8 and f1.4 The f1.4 is superior in every dept read my previos post if that s the way your going.Also dpending on budget the 85mm f1.4 is also superb right through the range
 
johnnymcclung said:
Because the 50mm focal length is closest to human eye perspective.
Click to expand...
Not even close.
A 50mm lens on a 35mm camera covers 46 degrees. With
a DX camera, it only covers 31 degrees.
An average, healthy human eye can see almost 180 degrees.
Of that 180 degrees, 135 degrees (give or take) of view can be
used to gauge depth.
A 14mm lens on a 35mm camera only covers 114 degrees.

Matt
 
I think the focal value (whatever it is) 45mm or 50mm on 35mm film, is closest to the human eye in terms of magnification, not degrees of view. I should have chosen a different word other than "perspective".
InitZero said:
InitZero said:
Because the 50mm focal length is closest to human eye perspective.
Click to expand...
Not even close.
A 50mm lens on a 35mm camera covers 46 degrees. With
a DX camera, it only covers 31 degrees.
An average, healthy human eye can see almost 180 degrees.
Of that 180 degrees, 135 degrees (give or take) of view can be
used to gauge depth.
A 14mm lens on a 35mm camera only covers 114 degrees.

Matt
Click to expand...
--
'Procrastinate now, don't put it off.'

 
If I close one eye, that's kind of what 50mm perspective looks like to me.

Also, I think the thing about 50mm is that when you look through the viewfinder on a FF body it doesn't appear to magnify or pull back from the view you'd get with one eye.

Just my thoughts.

--
Phil Flash
SF, CA USA
'Trust the 'kon!'

Stuff I own in my profile.
 
Exactly. If you look at a doorknob with your eye.... then look at the same doorknob through the viewfinder on a FF camera.. it will appear the same magnification (assuming you didn't move).
Phil Flash said:
If I close one eye, that's kind of what 50mm perspective looks like
to me.

Also, I think the thing about 50mm is that when you look through
the viewfinder on a FF body it doesn't appear to magnify or pull
back from the view you'd get with one eye.

Just my thoughts.

--
Phil Flash
SF, CA USA
'Trust the 'kon!'

Stuff I own in my profile.
Click to expand...
--
'Procrastinate now, don't put it off.'

 
That's not because it's a normal lens though... that just means the viewfinder magnification is about 1.0x.

Conversely, if you put a magnifier on the eyepiece, and the doorknob looks bigger than it does in real life that doesn't mean the lens isn't a normal. :-)
fudgebrown said:
Phil Flash said:
If I close one eye, that's kind of what 50mm perspective looks like
to me.

Also, I think the thing about 50mm is that when you look through
the viewfinder on a FF body it doesn't appear to magnify or pull
back from the view you'd get with one eye.

Just my thoughts.

--
Phil Flash
SF, CA USA
'Trust the 'kon!'

Stuff I own in my profile.
Click to expand...
--
'Procrastinate now, don't put it off.'

Click to expand...
 
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