olympus crop factor

Per Olof Pettersson said:

Denny Colvin said:

You keep building that strawman. If the noise characteristics are
indistinguishable for the particular photography you're doing, then
that's meaningless, isn't it?

Click to expand...

This is exactly the point. We are trying to come up with what
equivalent lens means. That means that there is not supposed to be
any differences. Then we can use that to compare lenses between
the two systems.

Click to expand...

No, we're not trying to come up with what equivalent lens means, since on different formats that is impossible. The OP asked about 35mm equivalent FOV on 4/3, nothing else. He didn't ask to be bombarded with circle of confusion, depth of field, 'light gathering ability', or noise.

... as that's been the weakness of all Oly DSLR's to date, along with less capability to focus in low light compared to Nikon and Canon cameras. But as the Sunday Bird threads have shown, you can get good bird-in-flight results using even an old E-1.

The more demanding the tracking situation the better off you'll be shooting at an aperture that gives you depth-of-field to spare. As nice as Oly lenses are wide open, I try to shoot stopped down as much as I can to give AF the best chance to succeed.
--
Street: http://www.wonderworks.com/streetphotographydigest.html
Flickr: http://www.flickr.com/photos/kyle_jones/

I agree with most you say except the sensor capturing 4 times as much light. That quite doesn't make much sense to me, given you are taking an image through a lens and projecting it, if anything I would say you get a higher light density on the projected image on the 4/3rds sensor due to being a smaller projection- meaning both should be exposed (35mm film, 5D format, 4/3rds) to the same amount of light energy, unless I a missing something that goes away in the lens do to inherent optics that I am not counting on.

In fact, if the bigger sensor was capturing 4 times the light then the ISO increase-need wouldn't probably happen to the same degree.

--
Raist3d
Photographer & Tools/Systems/Gui Vid Games Programmer

Mike,

Effectively, yes. But your numbers are a little off. Both the Canon and Olympus use sensors smaller than a conventional 35mm film negative. So the field of view is smaller. To get the same image in film would require a longer lens, which is the effect folks are talking about. For the Olympus, is a 2x effect. For Canon 30D it is 1.6x.

Working this out, a 300mm lens on the Canon 30D would have approximately the same field of view as a 480mm lens on 35mm film, or about the same as a 240mm lens on the Olympus. So the 50-200 on the E-510 would not have quite the same reach as the 300 on the Canon 30D, but it would be kinda close.

There are other issues related to depth of field, etc., but those aren't worth going into unless you're interested. If you're using the set up for sports or action, there's supposedly a new version of the 50-200 coming out with an SWD motor -- and hopefully faster focusing.

Hope this helps,

Jeff

mikenike said:

Good afternoon. Reading your forums do I understand that any lens
focal length is doubled with oly bodies? In other words if I purchase
a 510 or the new e3 and I put the 50-200 oly lens on it I will get a
35mm equivelment of 100-400 factor. If this is correct that would be
a better bif setup for me compared to my canon 30d and 300 f/4.0 set
up. Would love to hear your thoughts and opinions on this. Thank you

Click to expand...

--
Jeff

postulation and misinformation posted in this thread.

If I understand correctly, based on some of the replies above, shooting my 24mm f/1.8 on my E-1 is actually equivalent to shooting a 48mm f/3.5 on a 24x36 sensor. That is incorrect! While the EFL, compared to a 24x36 sensor may be 48mm, the f/stop is unchanged as my lightmeter indicates.

The OP asked a simple question and it was answered concisely by Denny Colvin in the first reply. For the most part, the balance of the replies have had nothing to do with the OP's initial question rather a bit of measurbating regarding issues that were not raised in the very simple question asked by the OP.
Very silly...
--
Troll Whisperer
Bill Turner

Bill,

Point well made. Danny almost answered the question in the first reply, but didn't catch the 1.6x factor for the 30D. But he had the right idea, and corrected it later.

With regard to your 24 f/1.8 on E-1 compared to 48 f/3.5 on 24x36, you need to do one more thing. That is to adjust the ISO. Then you can have same field of view, same depth of field, same shutter speed, and same exposure -- that is, just those things that have a visible impact in the final image. The OP didn't ask about all that, though.

Cheers,
Jeff

Bootstrap said:

postulation and misinformation posted in this thread.
If I understand correctly, based on some of the replies above,
shooting my 24mm f/1.8 on my E-1 is actually equivalent to shooting
a 48mm f/3.5 on a 24x36 sensor. That is incorrect! While the EFL,
compared to a 24x36 sensor may be 48mm, the f/stop is unchanged as my
lightmeter indicates.
The OP asked a simple question and it was answered concisely by Denny
Colvin in the first reply. For the most part, the balance of the
replies have had nothing to do with the OP's initial question rather
a bit of measurbating regarding issues that were not raised in the
very simple question asked by the OP.
Very silly...
--
Troll Whisperer
Bill Turner

Click to expand...

--
Jeff

Jeff said:

Bill,

With regard to your 24 f/1.8 on E-1 compared to 48 f/3.5 on 24x36,
you need to do one more thing. That is to adjust the ISO. Then you
can have same field of view, same depth of field, same shutter speed,
and same exposure -- that is, just those things that have a visible
impact in the final image. The OP didn't ask about all that, though.

Click to expand...

Correct you are and after shooting for more years than I care to recall, I completely understand.

For new shooters, and no disrespect intended, it's sometimes necessary to make small steps before getting the big picture. (Pun intended)

Jeff said:

Bootstrap said:

postulation and misinformation posted in this thread.
If I understand correctly, based on some of the replies above,
shooting my 24mm f/1.8 on my E-1 is actually equivalent to shooting
a 48mm f/3.5 on a 24x36 sensor. That is incorrect! While the EFL,
compared to a 24x36 sensor may be 48mm, the f/stop is unchanged as my
lightmeter indicates.
The OP asked a simple question and it was answered concisely by Denny
Colvin in the first reply. For the most part, the balance of the
replies have had nothing to do with the OP's initial question rather
a bit of measurbating regarding issues that were not raised in the
very simple question asked by the OP.
Very silly...
--
Troll Whisperer
Bill Turner

Click to expand...

--
Jeff

Click to expand...

--
Troll Whisperer
Bill Turner

congratulations, you just added to the "postulation and misinformation" by stepping into the same aformentioned equivalency hoohoo pile.

Bootstrap said:

postulation and misinformation posted in this thread.
If I understand correctly, based on some of the replies above,
shooting my 24mm f/1.8 on my E-1 is actually equivalent to shooting
a 48mm f/3.5 on a 24x36 sensor. That is incorrect! While the EFL,
compared to a 24x36 sensor may be 48mm, the f/stop is unchanged as my
lightmeter indicates.
The OP asked a simple question and it was answered concisely by Denny
Colvin in the first reply. For the most part, the balance of the
replies have had nothing to do with the OP's initial question rather
a bit of measurbating regarding issues that were not raised in the
very simple question asked by the OP.
Very silly...
--
Troll Whisperer
Bill Turner

Click to expand...

I like the technical bits of photography as much as anyone (being an engineer), but have to say that a lot of this detail is misplaced.

It does take a while to get really comfortable with Oly's somewhat smaller format. By that I mean using larger apertures (yes, it's ok to use f/2), finding the lenses sweet spots (f/4 -f/5.6 or so), and that 22mm is not really wide angle. So I did the math analysis once which helped me understand what's going on, but otherwise its just no longer part of thinking in setting up a shot. One just learns to deal with it in it's own native terms, and to calibrate to others when they're shooting a different format.

Sort of like getting used to thinking in kilometers without mentally converting to miles every time.

Best,
Jeff

Bootstrap said:

Jeff said:

Bill,

With regard to your 24 f/1.8 on E-1 compared to 48 f/3.5 on 24x36,
you need to do one more thing. That is to adjust the ISO. Then you
can have same field of view, same depth of field, same shutter speed,
and same exposure -- that is, just those things that have a visible
impact in the final image. The OP didn't ask about all that, though.

Click to expand...

Correct you are and after shooting for more years than I care to
recall, I completely understand.
For new shooters, and no disrespect intended, it's sometimes
necessary to make small steps before getting the big picture. (Pun
intended)

Bootstrap said:

Bootstrap said:

postulation and misinformation posted in this thread.
If I understand correctly, based on some of the replies above,
shooting my 24mm f/1.8 on my E-1 is actually equivalent to shooting
a 48mm f/3.5 on a 24x36 sensor. That is incorrect! While the EFL,
compared to a 24x36 sensor may be 48mm, the f/stop is unchanged as my
lightmeter indicates.
The OP asked a simple question and it was answered concisely by Denny
Colvin in the first reply. For the most part, the balance of the
replies have had nothing to do with the OP's initial question rather
a bit of measurbating regarding issues that were not raised in the
very simple question asked by the OP.
Very silly...
--
Troll Whisperer
Bill Turner

Click to expand...

--
Jeff

Click to expand...

--
Troll Whisperer
Bill Turner

Click to expand...

--
Jeff

Perry Jacobs said:

congratulations, you just added to the "postulation and
misinformation" by stepping into the same aformentioned equivalency
hoohoo pile.

Click to expand...

In what way?
--
Troll Whisperer
Bill Turner

Jeff said:

It does take a while to get really comfortable with Oly's somewhat
smaller format. By that I mean using larger apertures (yes, it's ok
to use f/2), finding the lenses sweet spots (f/4 -f/5.6 or so), and
that 22mm is not really wide angle. So I did the math analysis once
which helped me understand what's going on, but otherwise its just no
longer part of thinking in setting up a shot. One just learns to deal
with it in it's own native terms, and to calibrate to others when
they're shooting a different format.

Sort of like getting used to thinking in kilometers without mentally
converting to miles every time.

Click to expand...

Exactly!
--
Troll Whisperer
Bill Turner

"If I understand correctly, based on some of the replies above, shooting my 24mm f/1.8 on my E-1 is actually equivalent to shooting a 48mm f/3.5 on a 24x36 sensor. That is incorrect!"

Bump the iso up on the 24x36 and the statement is correct.

Perhaps you were making another point?

Bootstrap said:

Perry Jacobs said:

congratulations, you just added to the "postulation and
misinformation" by stepping into the same aformentioned equivalency
hoohoo pile.

Click to expand...

In what way?
--
Troll Whisperer
Bill Turner

Click to expand...

Everyone knows what we get with the 4/3 system compared to 35 mm. What difference does it make what we call it? Yet, we keep getting this ridiculous argument.

No its not because its STILL a 24 1.8. Period.

Simple question, simple answer...

The 50-200 on 4/3 gives the same magnification as a 100-400 legacy lens on a 24x36 (35mm) sensor. If you click the shutter, that's what you will get - 2x what you would have taken with, say, a 5D, using a lens of the same focal length.

DOF will be deeper, but that's not necessarily a bad thing. You can cut DOF back by cranking open the aperture. Fortunately, the 50-200 (a magnificent lens, by the way, I love mine) is a fast lens, so this is possible. Why the DOF is deeper is irrelevant - just know that it is a bit deeper, and you can correct for this if you so desire by opening up the aperture.

More techie: dedicated 4/3 lenses Do Not Have A Crop Factor! The image circle is optimized for a 4/3 sensor, so by Canon's definition, 4/3 is also Full Frame. Just a smaller frame. It's one of the benefits of designing a lens system specifically for digital, unlike practically every other maker who uses a legacy film lens mount design.

With a legacy film lens on a 4/3 camera (using an adapter), there is a crop factor, as you're only using a portion of the image circle at the back. Does it matter? For all practical purposes, not really. I use both the 50-200, and a legacy Nikkor 400 3.5. Both work quite well, though the big Nikkor can be a bit unwieldy - it's a seven pound lens, and really doesn't do well with subjects closer than 10-20 meters.

yeah i had forgotten about that

to meet the longer equivalent focal length (EFL) on 4/3rds a longer lens must be used of course
but the effect of the longer FL means its shortest focus is usually longer

Olympus 4/3 400mm EFL = 200mm x 2.0
Canon APS C 400mm EFL = 250mm x 1.6
--
Riley

I like to think the bs can never be higher than the ah

Stand in one spot, and with the same lens shoot with two cameras with different format sensors. You will get different images. Conclusions

==> Yes, 24mm f/1.8 is the same on either camera
==> No, the resulting images are different.
==> to get the same image, you need different lenses with different setup

Thisjustin said:

No its not because its STILL a 24 1.8. Period.

Click to expand...

--
Jeff

Bootstrap said:

postulation and misinformation posted in this thread.
If I understand correctly, based on some of the replies above,
shooting my 24mm f/1.8 on my E-1 is actually equivalent to shooting
a 48mm f/3.5 on a 24x36 sensor. That is incorrect!
--
Troll Whisperer
Bill Turner

Click to expand...

The 24mm f/1.8 at ISO 100 on E-1 is equivalent to 48mm f/3.5 on a 24x36 sensor at ISO 400. Yes the OP asked a very simple question, and you added misinformation to it.

--
CW

Denny Colvin said:

No, we're not trying to come up with what equivalent lens means,
since on different formats that is impossible.

Click to expand...

The whole point is that this is not impossible. In most photographic settings, you can make photos with a 4/3, APS-C and 135 format sensor, and someone investigating the image content could not possible tell the difference. That is total photographic equivalence, not just field of view.

Simon

Raist3d said:

I agree with most you say except the sensor capturing 4 times as much
light.

Click to expand...

The f-number is a measure for the intensity of light on the sensor (per unit area!). So, for an equal f-number, a 4 times larger sensor will collect four times as much light.

Of course, lenses for smaller sensors are often a little brighter, but that does not make up for the full extent of the difference.

Member said:

In fact, if the bigger sensor was capturing 4 times the light then
the ISO increase-need wouldn't probably happen to the same degree.

Click to expand...

I'm not sure I understand what you mean. The collection of more light, means that, at a given ISO value (defined by f-number, not total light collected), a larger sensor has more light to work with, and gives a cleaner signal. This is the cause of the inherent 'noise-problem' of smaller sensors. Of course, whether the noise is really problematic or not, is up to you.

Simon