Primes 'v' 2.8 Zoom

I am looking to change to a full frame body. I have waited for long enough
for the 5D replacement, so am considering going for a D700 because in all
honesty, spec wise the D700 has everything I want out of a body anyway.

At the moment, below 70mm, I use a 24 f/1.4 prime and a 50 f/1.2 prime on a
1.6X cropped body, which I love. But, of course there are times when a zoom
would be more convenient. So, I am torn between 85mm and 35mm primes, or
the 24-70 f/2.8.

I am happy with the DOF on my primes and most of the time use around f/1.8
for people shots if I want separation from the background. Given that I
will be moving from a cropped body to a full frame, mathematically the DOF @
2.8 will be about the same as my primes @ f/1.8.

I have been looking on the net at photos taken with 24-70 2.8 lenses on full
frame bodies, but what I find strange is that the DOF @ f/2.8 doesn't look
the same as it does on my primes @ f/1.8. Am I missing something?

Anyone have a logical reason why for example the DOF on a similar photo
taken @ 38mm f/2.8 full frame would be different to 24mm f/1.8 on a 1.6X
cropped body? The only thing I can think of is that the photos have been
cropped in post production, whereas mine haven't (so they were in fact
further away from the subject). Or maybe the bokeh is just nicer on my
primes, which makes it look different?

Jake wrote:
I am looking to change to a full frame body. I have waited for long
enough for the 5D replacement, so am considering going for a D700
because in all honesty, spec wise the D700 has everything I want out of
a body anyway.

At the moment, below 70mm, I use a 24 f/1.4 prime and a 50 f/1.2 prime
on a 1.6X cropped body, which I love. But, of course there are times
when a zoom would be more convenient. So, I am torn between 85mm and
35mm primes, or the 24-70 f/2.8.

I am happy with the DOF on my primes and most of the time use around
f/1.8 for people shots if I want separation from the background. Given
that I will be moving from a cropped body to a full frame,
mathematically the DOF @ 2.8 will be about the same as my primes @ f/1.8.

I have been looking on the net at photos taken with 24-70 2.8 lenses on
full frame bodies, but what I find strange is that the DOF @ f/2.8
doesn't look the same as it does on my primes @ f/1.8. Am I missing
something?

Anyone have a logical reason why for example the DOF on a similar photo
taken @ 38mm f/2.8 full frame would be different to 24mm f/1.8 on a 1.6X
cropped body? The only thing I can think of is that the photos have
been cropped in post production, whereas mine haven't (so they were in
fact further away from the subject). Or maybe the bokeh is just nicer
on my primes, which makes it look different?





It really is a case of "Suck it and see..." here. There are very few camera
retail stores that will not let you try a new lens on your body, or your
lens on a new body - using your own storage medium, and take the resulting
images home to play with. My camera store will let me take new equipment
out of the store to play with as long as I leave a credit card for them to
play with if I don't bring it back.

Cheers

BlackShadow

"BlackShadow" wrote in message
...
Jake wrote:
I am looking to change to a full frame body. I have waited for long
enough for the 5D replacement, so am considering going for a D700 because
in all honesty, spec wise the D700 has everything I want out of a body
anyway.

At the moment, below 70mm, I use a 24 f/1.4 prime and a 50 f/1.2 prime on
a 1.6X cropped body, which I love. But, of course there are times when a
zoom would be more convenient. So, I am torn between 85mm and 35mm
primes, or the 24-70 f/2.8.

I am happy with the DOF on my primes and most of the time use around
f/1.8 for people shots if I want separation from the background. Given
that I will be moving from a cropped body to a full frame, mathematically
the DOF @ 2.8 will be about the same as my primes @ f/1.8.

I have been looking on the net at photos taken with 24-70 2.8 lenses on
full frame bodies, but what I find strange is that the DOF @ f/2.8
doesn't look the same as it does on my primes @ f/1.8. Am I missing
something?

Anyone have a logical reason why for example the DOF on a similar photo
taken @ 38mm f/2.8 full frame would be different to 24mm f/1.8 on a 1.6X
cropped body? The only thing I can think of is that the photos have been
cropped in post production, whereas mine haven't (so they were in fact
further away from the subject). Or maybe the bokeh is just nicer on my
primes, which makes it look different?




It really is a case of "Suck it and see..." here. There are very few
camera retail stores that will not let you try a new lens on your body, or
your lens on a new body - using your own storage medium, and take the
resulting images home to play with. My camera store will let me take new
equipment out of the store to play with as long as I leave a credit card
for them to play with if I don't bring it back.

So if I buy the lens after you played with it, I am effectively buying an
used lens! It should be sold as a demo in that case, new means new!

No Spam wrote:
"BlackShadow" wrote in message
...
Jake wrote:
I am looking to change to a full frame body. I have waited for long
enough for the 5D replacement, so am considering going for a D700 because
in all honesty, spec wise the D700 has everything I want out of a body
anyway.

At the moment, below 70mm, I use a 24 f/1.4 prime and a 50 f/1.2 prime on
a 1.6X cropped body, which I love. But, of course there are times when a
zoom would be more convenient. So, I am torn between 85mm and 35mm
primes, or the 24-70 f/2.8.

I am happy with the DOF on my primes and most of the time use around
f/1.8 for people shots if I want separation from the background. Given
that I will be moving from a cropped body to a full frame, mathematically
the DOF @ 2.8 will be about the same as my primes @ f/1.8.

I have been looking on the net at photos taken with 24-70 2.8 lenses on
full frame bodies, but what I find strange is that the DOF @ f/2.8
doesn't look the same as it does on my primes @ f/1.8. Am I missing
something?

Anyone have a logical reason why for example the DOF on a similar photo
taken @ 38mm f/2.8 full frame would be different to 24mm f/1.8 on a 1.6X
cropped body? The only thing I can think of is that the photos have been
cropped in post production, whereas mine haven't (so they were in fact
further away from the subject). Or maybe the bokeh is just nicer on my
primes, which makes it look different?



It really is a case of "Suck it and see..." here. There are very few
camera retail stores that will not let you try a new lens on your body, or
your lens on a new body - using your own storage medium, and take the
resulting images home to play with. My camera store will let me take new
equipment out of the store to play with as long as I leave a credit card
for them to play with if I don't bring it back.

So if I buy the lens after you played with it, I am effectively buying an
used lens! It should be sold as a demo in that case, new means new!




They are sold as "shop" lenses for that very reason. It is often a way to
get a good deal, as they still have full warranty etc.

BlackShadow

On 2008-08-30 06:19:58 -0700, "Jake" said:

I have been looking on the net at photos taken with 24-70 2.8 lenses on
full frame bodies, but what I find strange is that the DOF @ f/2.8
doesn't look the same as it does on my primes @ f/1.8. Am I missing
something?

Yes. Try taking the same picture at f/2.8 with a prime and crop it to
the same field of view as the zoom on the DSLR. The DOF should be the
same. You will see that 50mm on a 35mm camera is not really equivalent
to 38mm on a digital camera. It is still a 38mm lens; all you did was
crop the edges off.
--
Waddling Eagle
World Famous Flight Instructor

"C J Campbell" wrote in message
news:2008083009244975249-christophercampbell@hotmailcom...

I have been looking on the net at photos taken with 24-70 2.8 lenses on
full frame bodies, but what I find strange is that the DOF @ f/2.8
doesn't look the same as it does on my primes @ f/1.8. Am I missing
something?

Yes. Try taking the same picture at f/2.8 with a prime and crop it to the
same field of view as the zoom on the DSLR. The DOF should be the same.
You will see that 50mm on a 35mm camera is not really equivalent to 38mm
on a digital camera. It is still a 38mm lens; all you did was crop the
edges off.

Thanks for the reply, however I think that you have missed the point. It's
understandable though, as it's a bit full on and was expecting that it would
be mis-interpreted. In reality, it's a prime 'v' zoom comparison, with a
difference being different sensor sized bodies too.

I am not interested in post process cropping in this post, as I do all my
cropping through the viewfinder. So if I want a big area of sky to put text
into, I judge this through the viewfinder. If I want a square image, I
judge this through the viewfinder, etc.

Sometimes people look at cropped sensors, as just cropped sensors, but
forget that to frame the same image through the viewfinder with a bigger
sensor means that you have to get closer to the subject. This results in a
narrower DOF.

On Sat, 30 Aug 2008 19:55:21 +0100, "Jake" wrote:
: "C J Campbell" wrote in message
: news:2008083009244975249-christophercampbell@hotmailcom...
:
: I have been looking on the net at photos taken with 24-70 2.8 lenses on
: full frame bodies, but what I find strange is that the DOF @ f/2.8
: doesn't look the same as it does on my primes @ f/1.8. Am I missing
: something?
:
: Yes. Try taking the same picture at f/2.8 with a prime and crop it to the
: same field of view as the zoom on the DSLR. The DOF should be the same.
: You will see that 50mm on a 35mm camera is not really equivalent to 38mm
: on a digital camera. It is still a 38mm lens; all you did was crop the
: edges off.
:
: Thanks for the reply, however I think that you have missed the point. It's
: understandable though, as it's a bit full on and was expecting that it would
: be mis-interpreted. In reality, it's a prime 'v' zoom comparison, with a
: difference being different sensor sized bodies too.
:
: I am not interested in post process cropping in this post, as I do all my
: cropping through the viewfinder. So if I want a big area of sky to put text
: into, I judge this through the viewfinder. If I want a square image, I
: judge this through the viewfinder, etc.

It doesn't matter where you do your cropping. As CJ says, the DOF of a lens,
for a given camera-to-subject distance, depends only on the lens's focal
length and aperature.

: Sometimes people look at cropped sensors, as just cropped sensors, but
: forget that to frame the same image through the viewfinder with a bigger
: sensor means that you have to get closer to the subject. This results in a
: narrower DOF.

But that's an entirely different matter. You said you've been looking at
pictures on the net, not performing direct comparisons at measured distances.
How do you know what the camera-to-subject distances were in those pictures?

Bob

"Jake" wrote:

I am looking to change to a full frame body. I have waited for long enough
for the 5D replacement


Do you mean that you really cannot wait until Photokina, when the 5D
replacement(s) will be announced?

http://photokina.en.koelnmesse.info/

September 23-28, 2008. Cologne, Germany.

** Posted from http://www.teranews.com **

"Bruce" wrote in message
...

I am looking to change to a full frame body. I have waited for long
enough
for the 5D replacement


Do you mean that you really cannot wait until Photokina, when the 5D
replacement(s) will be announced?

http://photokina.en.koelnmesse.info/


Mmm, I don't think it will though. Never say never though. No
announcements yet, only the 50D.
http://www.photokina-show.com/canon/

Mind you, I will also be interested to see some real life low light shots
from the 50D to see how it holds up with noise at high ISO giving the
increased pixel density. I am guessing that it will have a stop more
usability (IE, ISO 3200 on the 50D will be the same as ISO 1600 on the 40D),
but will have to see. Will also be interesting to see how much the camera
slows down (Max burst) if in-camera processing is needed to get good low
noise results.

"Robert Coe" wrote in message
...

: I have been looking on the net at photos taken with 24-70 2.8 lenses
on
: full frame bodies, but what I find strange is that the DOF @ f/2.8
: doesn't look the same as it does on my primes @ f/1.8. Am I missing
: something?
:
: Yes. Try taking the same picture at f/2.8 with a prime and crop it to
the
: same field of view as the zoom on the DSLR. The DOF should be the
same.
: You will see that 50mm on a 35mm camera is not really equivalent to
38mm
: on a digital camera. It is still a 38mm lens; all you did was crop the
: edges off.
:
: Thanks for the reply, however I think that you have missed the point.
It's
: understandable though, as it's a bit full on and was expecting that it
would
: be mis-interpreted. In reality, it's a prime 'v' zoom comparison, with
a
: difference being different sensor sized bodies too.
:
: I am not interested in post process cropping in this post, as I do all
my
: cropping through the viewfinder. So if I want a big area of sky to put
text
: into, I judge this through the viewfinder. If I want a square image, I
: judge this through the viewfinder, etc.

It doesn't matter where you do your cropping. As CJ says, the DOF of a
lens,
for a given camera-to-subject distance, depends only on the lens's focal
length and aperature.

: Sometimes people look at cropped sensors, as just cropped sensors, but
: forget that to frame the same image through the viewfinder with a bigger
: sensor means that you have to get closer to the subject. This results
in a
: narrower DOF.

But that's an entirely different matter. You said you've been looking at
pictures on the net, not performing direct comparisons at measured
distances.
How do you know what the camera-to-subject distances were in those
pictures?

Bob



I think I will have to try a zoom and see how I get on with it. I guess
it's the only real way.

It would be good it I can get away with the 24-70, as it will mean I will
have 3 lenses in one. Less changing lenses, less cost, less weight, etc.
Still a bit skeptical on how it will compare to primes though. ;-)