Why Four Thirds is better - Lets continue here

[Jay Turberville]

F/2.0 on 4/3 system is not brigher than 2.8 on full frame 135mm.

Hmmm... Then why is one f2 and the other f2.8?

Nah.. nice try but I think you're wrong! F2 is F2 is F2 whatever
the format! Unless someone wants to educate me on why he's right?

Yep. F/2 is f/2. Just like 50mm is 50mm. And just like focal length, f-ratios on a smaller formats give different results in final prints of the same size. And the smaller sensor size makes larger apertures more important if you intend to keep noise and DoF capabilities equivalent.

So f/2 is f/2. But if you are comparing different formats, you need to figure out the equivalencies of their effects. Just like you have to for focal length.

What Olympus did with their lens in
comparison to the sensor size is indeed larger because the image
area is 1/4 of the full frame lens,

Which lets in more light for the size of the format! f2 is brighter
than f2.8!

Yep. F/2 lets in more intense light than f/2.8. But (assuming sensors with the same photosite count) if you want the same total number of photons per photosite (aka pixel) so that shutter speed and S/N will be equivalent, then the smaller sensor needs the extra speed - just to maintain parity. It also needs the faster f-ratio it to maintain parity with shallow DoF.

--
Jay Turberville
http://www.jayandwanda.com

 

[Jay Turberville]

But you won't convince me that a 35mm/DX/APS size f2 zoom will have
the same 'corner to corner' image quality and non-vignetting as an
Oly F2 zoom if it has been made smaller.

For equivalency, the 35mm only needs to have an f/4 zoom. The DX just needs an f/2.8 zoom.

--
Jay Turberville
http://www.jayandwanda.com

 

[Jay Turberville]

I got even better results with assorted Nikkors, old and new. Jay,
you're preaching to the choir on this one.

Well, the 50mm f/1.4 Takumar is great - very even illumination at
f/2.0. I haven't checked the 50-300mm f/4.5 ED Nikkor.

I took some wide open shots of the sky today (very clear day) to check out the 50-300 f/4.5 ED Nikkor. At 50mm, the mean falloff in the corners was around 1/4 of a stop. It progressively increased as I zoomed in steps to 300mm. At 300mm it was a little more than half a stop. That surprised me a bit.

Visual inspection showed that the exit pupil of the 50-300 doesn't change at all as the lens is zoomed.

But a bit more than half a stop of falloff isn't much of a problem for me at all. I didn't check to see if the vignetting improved with stopping down. I'm guessing that it does, but maybe not.

--
Jay Turberville
http://www.jayandwanda.com

 

[Joseph S Wisniewski]

My name is Joseph.

Address me as such, and I will reply.

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[Joseph S Wisniewski]

I don't like my 4/3 gear because it's 4/3, I like it because
Olympus makes it. They turn out a Quality product.

I'm not sure who you are agreeing or disagreeing with.

I have stated, multiple times, that the Oly's are good cameras in spite of being four thirds (tm) cameras, not because of it.

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[Joseph S Wisniewski]

I think a more interesting discussion is what will be the impact of
the offset microlens sensor on the future of digital photography.

I've been advocating offset microlenses for years. Now Kodak, Oly's
original four thirds (tm) partner, is supplying such a sensor to
Leica.

http://www.dpreview.com/news/0609/06091501kodakccdleicam8.asp

An offset microlens sensor negates the arguments about needing new
"near telecentric" lenses for digital photography.

As that's what they'd need to handle. They'd have to take the light
from a 7(14) mm wide angles to a 500(1000) mm tele!

Can they do it? I'd think the wide angles would be difficult
without some form of telecentricity on the lenses if you wanted to
avoid vignetting? But you'd know more about it than me.

They work quite well with lenses from wide angle to telephoto.

http://forums.dpreview.com/forums/read.asp?forum=1000&message=20006094&q=offset+microlenses&qf=m

Any DSLR is going to have retrofocus wide angles, that's a requirement imposed by having a reflex mirror. For an SLR, you always need sqrt(2) * vertical sensor height (plus a few mm to account for shutter and sensor cover glass) between the sensor and the rear element of the lens. For full frame, that's about 39mm. The actual number ends up about 90% of the sensor diagonal. The exit pupil is always a few mm in front of the rear element, all the full frame wide angles I've measured have been at least 52mm, and the sensor diagonal is 43.3mm. So, the very worst case angle you can have is arctan(43.3mm/2/52mm) = 22.6 degrees. Now, both theoretical calculations and my experience with over a dozen real DSLRs of various sensor types and sizes show that 22 deg is a problem, but that no known camera has a problem at 15 degrees. Jay Tuberville's measurements on four thirds DSLRs with full frame lenses support the freedom from problems at 15 degrees even on the sensors Oly uses.

To get from 22.6 degrees to 15 degrees requires only a 7.6 degree offset to the microlenses. Will that hurt a telephoto? Obviously not, because an infinitely long telephoto would have light perfectly perpendicular to the sensor, and the 7.6 degree offset would have the same effect as if that formerly perpendicular light were now 7.6 degrees from perpendicular. You won't notice 7.6 degrees.

--
Normally, a signature this small can't open its own jumpgate.

Ciao! Joe

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[Forrest41926]

24-105 IS + USM

Is that the canon lens with 5 stops worth of vignetting?

No idea, I've never used one. If you'd like to know about my 135/2 I'd be happy to tell you all about it, though.

Plus they're f4 + f4-5.6 lenses.. he was talking about f2.8-3.5
gear! What he gets in light gathering abilities... you get in
anti-shake. Snakes and ladders!

Funny how willing people are to apply the 2x crop in the Olympus system to the focal length but not to the aperture... That $7,000 Oly 300/2.8 is worth more than double a Canon 300/2.8 with IS because you're going to put it on a system where it "becomes" 600 mm ... but the objective lens is still 107 mm, so in effect it's a f/5.6 lens. In terms of DOF ( you loose much control over creative focus with the crop ) and the noise from using such a small chip balances the light-gathering ability perfectly.

Not trying to knock your system, but you're pretending to get a free lunch, which just isn't the case.

 

[Agramer]

Funny how willing people are to apply the 2x crop in the Olympus
system to the focal length but not to the aperture... That $7,000
Oly 300/2.8 is worth more than double a Canon 300/2.8 with IS
because you're going to put it on a system where it "becomes" 600
mm ... but the objective lens is still 107 mm, so in effect it's a
f/5.6 lens. In terms of DOF ( you loose much control over creative
focus with the crop ) and the noise from using such a small chip
balances the light-gathering ability perfectly.

Not trying to knock your system, but you're pretending to get a
free lunch, which just isn't the case.

How you get this number?? f5,6?? and much deeper DOF?

hmm. . .I didn't use this lens, but 50-200/2,8-3,5 is on 60mm/2,8 weeery close to 120-300/2,8 on 120/2,8. I didn't use milimeters, just my eyes.
Cheers

 

[David Banner]

From what I understand, the 4/3 system has more DoF and therefore makes it hard to isolate subjects for portraits. Is this true? Can its 2x crop factor be compared to the 1.6 of 400D? I shot with a friend who uses a 5D and I was amazed at how much less DoF there is on a FF camera. Much more creative control.

 

[Jon Ragnarsson]

Wide DoF on FT camera is not bad, only different.

From what I understand, the 4/3 system has more DoF and therefore
makes it hard to isolate subjects for portraits. Is this true?
Can its 2x crop factor be compared to the 1.6 of 400D? I shot with
a friend who uses a 5D and I was amazed at how much less DoF there
is on a FF camera. Much more creative control.

--
http://www.4-3system.com
http://jonr.light.is

 

[sngreen]

I think, i'm writing to follow that conversation about 4/3, and how
canon and nikon useres think their system are superior...

Yes, bigger sized sensor is better than a smaller one. Otherwise I would've bought P&S.

...

I love both cameras, but in some points I agree canon is better
(lots of lenses and acessories and the ISO results). Yes, the ISO
results. Canon users love to talk about. And the 7 or 9 focus
points. I only use one. The central one. Do you use more? Or other
one?

On E-500 for motion shots I usually use left or right point, depending on where the object is coming from. Some modern cameras also use multiple points for settings correct DOF - I always miss those through E-500 viewfinder. Using one single point with camera mounted on tripod is not always simple either. So yes, multiple points are better than only 3.

Isn't faster composing the scene than selecting the exact
match point (when it exists...)? And about the ISO (again): do you
use the ISO 1600 all the time? Don't you know ther is software to
remove noise?

Software also removes quite a lot of detail. And yes, very often I wish I could use higher ISO. See some of my evening examples here;

http://www.pbase.com/sngreen/nachtaufnahmen_von_wien

The E-500 has better built in flash modes, more user friendly menus
(you don't have to push the ok button to accept the modifications,
like canon does), the valious SSWF (new in 400D) and the kit lenses
better than canon.

I hardly ever use built in flash - it is just like throwing the shot away. The E-500 menues are better than on 350D - I agree - but I still need to press OK button to exit from the menu mode. The SSWF is not bad but it slows the camera startup and now almost every entry-level camera will have it. Ever wonder why only entry level cameras have it? Kit lenses are fine, but most people when buying dSLR are not planning to stay with kit lenses forever - Canon know it, Nikon know it, even Pentax have figured it out.

Yes, Zuiko lenses are faster and provide better
images (especially the 40-150 vs Canon EF 55-200).

You have to consider crop factor and speed/sensitivity of the camera. What is 2.8 for zuiko is not 2.8 for Canon or Nikon. Either of the later brands focus faster - so what is the zuiko speed about? And also, how do you define better images?

Yes, Canon has more than 60 lenses. 4/3 has only over 20.

I counted 33 macro lenses for modern Canon system (with Tamrons, Tokinas, and Sigmas), so it must be more than 60 all together.

But how
old is the 4/3 system? 3, maybe 4 years?

It is irrelevant - what is it to you as a consumer?

And everyone wants 60 lenses in that time?

No, not really, but I would like to have a good macro setup with at least 90mm in focal length. It would also be nice to have few fast primes. The telephoto is ok.

In my opinion, Zuiko, Leica, Sigma are
producing the essential range lenses.

Not so sure leica will be making much for 4/3rds - M8 has entirely different mount. Sigma is also not exactly jumping on board. Here in Vienna Sigmas for Olympus are not that easy to find.

Canon have more, right. But
in Canon, for example, you have 70-300, 75-300, I, II, III, IS, DO
IS... Almost the same focal distance in more than one lenses (and
same producer).

And what is wrong with that? I am sure there would be more zuiko 300mm buyers had there be more variants of it.

Zuiko didn't that, yet.

The 100mm macro has been on the roadmap for the last 2 years - I am yet to read it has been announced.

And about the image format: 3/2 vs 4/3. What's the problem? When
you publish an image, don't you crop it? >

Only to straighten it - I hardly crop otherwise.

I don't print all of my
fotos, but made pps prensentations to send to my friends, and
(guess) they all have 4/3 computer displays!

Well I just bought wide format 21" (23" equivalent) display - the images look not bad, but they could look better in different format.

Canon and Nikon users, respect the 4/3. It's like a freshman in
this things... And, beliver or not, is doing a great job.

Why do they buy Canons and Nikons then?

Olympus users, can you stop dreaming about the new E-X (Pro DSLR)?
The E-1 almost died, and we're all responsable about that. Now, at
the end of its line, everyone wants one... And why you want a new
Pro DSLR? Will you buy it? Or are you gonna wait until its death,
like E-1? In that case, canon users are better consumers...

I would buy one if I were sure Olympus would not let me down somewhere down the road. Now, same as you, I have my doubts.

• Sergey

 

[Louis_Dobson]

I have NO trouble isolating subjects on 4/3rds. The DoF is ENTITELY shallow enough (unlike a P&S). But on larger sensored cameras I am ALWAYS screabbling for more DoF.

For me, 4/3rds is the perfect DoF compromise.

I can have DoF when I need it, lose it when I don't.













--
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http://www.pbase.com/acam/

 

[sngreen]

I have NO trouble isolating subjects on 4/3rds. The DoF is
ENTITELY shallow enough (unlike a P&S). But on larger sensored
cameras I am ALWAYS screabbling for more DoF.

For me, 4/3rds is the perfect DoF compromise.

I can have DoF when I need it, lose it when I don't.

I like your colors and composition, Louis, but the DOF is marginal. As you come closer to the subject the DOF is becoming proportionally shallower, but you have hardly any control on it from the distance. I also noticed you use NeatImage – that tends to add additional blur on colors or area you select.

Here is a good Pentax example from this past winter – it is not mine – but I had it bookmarked nevertheless. It was posted last winter in Pentax forum. Note the distance and the amount of blur – in my book there is never enough of it but in this example it is just perfect.

 

[Louis_Dobson]

rarely use NeatImage, and generally only on a layer to sort out sky.

None of those shots, except the girl on the beach, is wide opne, and that's a slow lens.

That's my point - I almost never need the shallowness of the DoF I DO have available. The Pentax shot? No problem. That would have been easy with 4/3rds too. [Excellent shot, but the DoF is easy]

As I say, I like to leave enough back ground for there to be a context. Next one is 5.6, for example, because I want you to KNOW she is part of a crowd...

4/3rds works for me - because it gives me DoF control BOTH WAYS. 35mmFF, you are always scrabbling for DoF.





--
http://www.flickr.com/photos/acam
http://www.pbase.com/acam/

 

[Joseph S Wisniewski]

Funny how willing people are to apply the 2x crop in the Olympus
system to the focal length but not to the aperture... That $7,000
Oly 300/2.8 is worth more than double a Canon 300/2.8 with IS
because you're going to put it on a system where it "becomes" 600
mm ... but the objective lens is still 107 mm, so in effect it's a
f/5.6 lens. In terms of DOF ( you loose much control over creative
focus with the crop ) and the noise from using such a small chip
balances the light-gathering ability perfectly.

Not trying to knock your system, but you're pretending to get a
free lunch, which just isn't the case.

How you get this number?? f5,6?? and much deeper DOF?

Nope, f5.6 and same DOF.

Give it a try yourself.

http://www.dofmaster.com/dofjs.html

Let's punch in a 600mm f5.6 at 100 feet on full frame.

DOF = 2.82 feet.

Now we punch in a 300mm f2.8 at 100 feet on four thirds (tm).

DOF = 2.84 feet.

(there are reasons for the 0.7% difference that we won't get into here).

hmm. . .I didn't use this lens, but 50-200/2,8-3,5 is on 60mm/2,8
weeery close to 120-300/2,8 on 120/2,8. I didn't use milimeters,
just my eyes.

So do I' but I'm careful to restrict the examples so that I'm changing exactly one variable at a time

--
Normally, a signature this small can't open its own jumpgate.

Ciao! Joe

http://www.swissarmyfork.com

 

[Jay Turberville]

I have NO trouble isolating subjects on 4/3rds. The DoF is
ENTITELY shallow enough (unlike a P&S). But on larger sensored
cameras I am ALWAYS screabbling for more DoF.

What is sufficient DoF is certainly a matter of opinion. But the simple fact is that a 36x24mm lens has about a stop shallower DoF than a 1.5X DX camera, and the DX camera has about a stop less DoF than a 4/3s camera. I'll have to dig up the formula that someone gave me, but I think the DX camera is actually spaced at 1 1/3 stop from the 35mm format and 2/3 stop from the 4/3s format.

High DoF is the same for all formats. You simply stop down more. They are all limited by diffraction at the same degrees of high DoF. There should be no "scramble" unless the larger format doesn't have a high enough f-number. Just select a higher f-number.

--
Jay Turberville
http://www.jayandwanda.com

 

[Joseph S Wisniewski]

I have NO trouble isolating subjects on 4/3rds. The DoF is
ENTITELY shallow enough (unlike a P&S). But on larger sensored
cameras I am ALWAYS screabbling for more DoF.

What is sufficient DoF is certainly a matter of opinion. But the
simple fact is that a 36x24mm lens has about a stop shallower DoF
than a 1.5X DX camera, and the DX camera has about a stop less DoF
than a 4/3s camera. I'll have to dig up the formula that someone
gave me, but I think the DX camera is actually spaced at 1 1/3 stop
from the 35mm format and 2/3 stop from the 4/3s format.

It's not much of a format, equivalent aperture is simply in proportion to the sensor diagonal. If you want to figure "stops", square it and tale the log base two. If we call DX a 1.5x crop and four thirds (tm) a 2x crop, then DX is 1.17 (or 1 1/6) stop from FF, four thirds is 0/83 (5/6) stop from DX, or an even two stops from FF.

Neat thing is that the same math also applies to ISO, because noise scales with sensor size.

Of course, that doesn't tell the whole story, because the systems line up like this when you consider available lenses in the portrait ranges...

full frame
50mm f1.4 with ok bokeh, a bit marginal wide open, but great closed down a stop.
(that was a bit wide, now we get serious)
85mm f1.4 or f1.2 with amazing bokeh
105mm f2.0 with amazing bokeh
135mm f2.0 with amazing bokeh

DX
42mm f2.1 (28mm f1.4) with great bokeh

45mm f2.1 (30mm f1.4 Sigma) with good bokeh, a bit marginal wide open, but great closed down a stop.

75mm f2.1 (50mm f1.4) with ok bokeh, a bit marginal wide open, but great closed down a stop.
(that hurts a bit, 75mm is a little short, and not the best).
127mm f2.1 (85mm f1.4) with amazing bokeh

four thirds (tm)

60mm f2.8 (30mm f1.4 Sigma) with good bokeh, a bit marginal wide open, but great closed down a stop.
(as far as a classic portrait lens, that's quite short and quite slow).
100mm f4.0 (50mm f2.0 macro) with horrible bokeh.
70-200mm f4.0 (35-100mm f2) zoom.

(Normally, I wouldn't throw in a zoom, especially one so large, expensive, and slow, but it's as close to a portrait lens as Oly has).

High DoF is the same for all formats. You simply stop down more.
They are all limited by diffraction at the same degrees of high
DoF. There should be no "scramble" unless the larger format
doesn't have a high enough f-number. Just select a higher f-number.

Yup. I was wondering about Louis's comments there, too.

--
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Ciao! Joe

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[Joseph S Wisniewski]

I'm waiting for new pro build 4/3 camera with 5fps, cca 10mpix and
some kind of IS/VR/AS... If it shows untill next summer i'll buy it
+ 11-22/2,8-3,5 and 35-100/2,0. If it doesn't show next yaear . .
.? I'll see next year

Well hopefully you'll get what you want from Olympus, because you
seem to enjoy your lenses ... and good glass ( by whatever measure
is important to you ) is a joy to use.

I like zooms because they are friendly they walk instead of me
I want a good prime just for a portraits. . .and I need them for
macros too.

Do you mind manual focus?

Get a Nikon 50mm f1.2 (not the 50mm f1.4) and a Nikon to four thirds (tm) adapter. That's equivalent to a 100mm f2.4 on four thirds. Back in the film days, my 105mm f2.5 was my favorite portrait lens, 100mm f2.5 is within 5% of that in both focal length and speed.

Or, if you've got a couple of grand to kill, find a used Nikon 58mm f1.2 NOCT. Best portrait lens you'll ever see at crop factors from 1.5x to 2x.

--
Normally, a signature this small can't open its own jumpgate.

Ciao! Joe

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[Jay Turberville]

It's not much of a format, equivalent aperture is simply in
proportion to the sensor diagonal. If you want to figure "stops",
square it and tale the log base two. If we call DX a 1.5x crop and
four thirds (tm) a 2x crop, then DX is 1.17 (or 1 1/6) stop from
FF, four thirds is 0/83 (5/6) stop from DX, or an even two stops
from FF.

Yeah. I always forget this math. Maybe it will stick this time.

Anyway, it is the 1.6 crop factor Canon cameras that fall at 1 1/3 stop from 35mm format and about 2/3 a stop from 4/3.

The reason the issue sticks with me is that there is a lot of estimating and lumping of categories that goes on with these discussions. Most of the rounding and estimating tends to "favor" "APS-C" class cameras. The bottom line is that the gap between 35mm format and the various "APS-C" cameras is larger than the gap between the "APS-C" class cameras and the Four Thirds standard.

Anyway, my math review and thinking about this issue again prompted me to put together a little Excel sheet using DPReview posted sensor dimensions. I've exported it as HTML. Some people might find this helpful when considering the differences between formats. I suspect the active pixel area of the non Four Thirds cameras listed might be a bit smaller than the numbers listed. But I'm listing the DPReview published numbers until and unless I can find something that says otherwise.

http://www.jayandwanda.com/photography/formats_and_stops.htm

Neat thing is that the same math also applies to ISO, because noise
scales with sensor size.

Assuming similar technological sophistication, yes. And as we were discussing, so does the DoF (assuming FoV and f-number are held constant).

Of course, that doesn't tell the whole story, because the systems
line up like this when you consider available lenses in the
portrait ranges...

Right. The particulars of what any individual photographer needs to do with his or her camera can be much more important than the general format considerations.

--
Jay Turberville
http://www.jayandwanda.com

 

[sngreen]

rarely use NeatImage, and generally only on a layer to sort out sky.

None of those shots, except the girl on the beach, is wide opne,
and that's a slow lens.

That's my point - I almost never need the shallowness of the DoF I
DO have available. The Pentax shot? No problem. That would have
been easy with 4/3rds too. [Excellent shot, but the DoF is easy]

As I say, I like to leave enough back ground for there to be a
context. Next one is 5.6, for example, because I want you to KNOW
she is part of a crowd...

4/3rds works for me - because it gives me DoF control BOTH WAYS.
35mmFF, you are always scrabbling for DoF.

Obviously there can be no wrong or right when discussing this subject. It appears that DOF between say 4/3 and Pentax does not differ much, but it is a background effect where things look different. In other words, if you notice, the closer subjects will always be in better focus than those placed on the other side but equally distant to what you focus on. And with larger sensors this effect is way more pronounced than with smaller ones. As in this example (this is not mine - was taken with D70 - way oversharpened but good enough to demonstrate the point);



All petals are in relatively good focus and yet the background is quite unrecognizable. In most cases (even with far placed backgrounds) I still get to recognize what is behind the flower even when I can no longer retain all needed details (as with the flower) in good focus. In fact this is one of my constant problems - when I aim for a shallower background I very often miss focus on where things should be clear - resulting of course in a throw-away image. From the film days as I remember the DOF would not necessarily be as shallow but the background would come quite blurry. It is not always possible for D70 - I can imagine - but it is even less so with 4/3.

Here are some of my flowers where (as in many cases) I wish the background was even more blurry;

http://www.pbase.com/sngreen/flowers

• Sergey