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Hasselblad lenses on Nikon digital

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Joseph,

MTF measurements are used because measurements of resolving power alone do not tell how well a lens performs. We need to know how visible the lp/mm the lens resolves are. And that is measured and plotted in MTF graphs.
So yes: MTF has a lot to do with both resolving power and our photographic experience.

The point however is that Zeiss do not publish MTF performance figures for resolutions above 40 lp/mm.
Their graphs do not tell us what the maximum, visible, resolution of a lens is, nor how the contrast is at that highest visible resolution.

So what is going on beyond 40 lp/mm remains to be guessed (and believe me, there are not many lenses that do not resolve 40 lp/mm).
MTF graphs do not offer proof that some lenses (35 mm format ones) have a higher resolving power than other lenses (larger format ones).

That, as you will see by now, still isn't "my" "way of measuring the resolving power".

Photodo has not only received a lot of criticism (largely justified, and mostly directed at the way they assign ratings based on very limited data), they also do only measure MTF at a limited number of spatial frequencies.

Now, Joseph, how about you providing the evidence for your statement?
"Do you measure this yourself ? Do you measure this yourself in order to come to the conclusion in your posting with no 31? If you don't measure this yourself how do you come to the conclusion?"
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And citing a couple of 35 mm format lenses that are stunning performers, like you do in response to Isidor, shows that there indeed are 35 mm lenses that are stunning performers, better, surely, than some/many MF lenses.

And yes, there certainly are such lenses! But before you begin spending much energy arguing along this line, remember that your "This is true" was a general statement, and not about some lenses.
 
In my experience:

Lenses from smaller formats outresolve lenses from bigger formats.

A few years ago, me and a fellow photogtapher found this through practical terms, not scientific but good and careful peeping with good lupes.

Same scene. Tripods. Both Velvia.
4X5 Calumet with a 105 Nikkor
F2 Nikon with a Nikkor 105 AI-S

35mm outresolved 4X5 by wide margin. Of course both were pointed out about just the same spot in the center of the lens.

Recently, I did a test with a 50mm Zeiss CF and an adapter to my 5D, comparing to a Canon Ef 50mm F1.8. Same thing. the Canon outresolved the Zeiss lens, but not for much. The canon won in resolution and contrast. both at f8.0.

In the end, bigger formats win because the much bigger real estate. But milimeter by milimeter, within the projected image by the lens, glass from smaller formats wins.

By the way, these results were true just about all around of the image, not only the center.

Eduardo
 
This is an old argument which always boils down to the circle of confusion of the lens design. As commonly thought 35 mm lenses resolve better than MF. While I could only vaguely remember the numbers, .030 for 35 and .060 for MF, I was surprised to read the following from CZ Camera Lens News # 2 1997.

"Resolutions on the same level
have been achieved with Carl Zeiss
lenses in Hasselblad medium format
cameras, proving that at Carl Zeiss,
medium format lenses, contrary to
popular belief, offer no lower
resolution than the very best 35 mm
lenses."

http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN02e/$File/CLN2.pdf

Regards:

Gilbert
 
Eduardo, good man !

Hi Ulrik,

I am interested in the truth and nothing else. I make statements when I have good evidence to support. "could be sharper...full confidence...would believe" are proposals which means evidences have not been gathered but were made from deductions from experience. I hope my readers do not confuse statements from proposals, so I use the terms could,would believe to distinguish proposals from statements.

Q.G was making a statement in post no. 1103 "No, Joseph is not correct that 35 mm format lenses have higher resolving power. " It is perfertly alright to disagree with someone if one has adequate evidence, but in this case Q.G. himself cannot provide us with any evidence at all.

I got these evidence after scanning many times. I got the evidence after reading carefully all the Zeiss MTF graphs. What has Q.G. done ? Disagreeing for the sake of disagreeing.

""Now, Joseph, how about you providing the evidence for your statement?
"Do you measure this yourself ? Do you measure this yourself in order to come to the conclusion in your posting with no 31? If you don't measure this yourself how do you come to the conclusion?"
I was asking QG questions and I was not making statements.

"No, Joseph is not correct that 35 mm format lenses have higher resolving power. " QG, if you are not measuring resolving power by line pair per mm, how do you know that I was wrong. QG has no evidence at all.
 
The Zeiss link provided by Gilbert apparently provides the evidence Joseph. Take the time to read it.

"Resolutions on the same level have been achieved with Carl Zeiss medium format lenses in Hasselblad medium format cameras, proving that at Carl Zeiss medium format lenses, contrary to popular belief, offer no lower resolution than the very best 35mm lenses."

Remember, this statement is from the very same company that makes "the very best 35mm lenses".

This is consistant with my experience using my Zeiss CF, CFi and CFE lenses on 35mm cameras compared to Zeiss and Leica 35mm optics ... including some of the best ones Zeiss ever made.

My contention is that if you have the 35mm lenses, why use the much more inconvenient MF ones? I did only as a matter of providing a pratical back-up to the primary MF camera should it fail. A Zeiss MF optic on a Canon 1DsMKII isn't as good as the same lens on a 503CWD because of the sensor, but it's better than nothing if the CFV fails on the job... which it never has. Then only one set of lenses need be packed instead of two.
 
Joseph, thanks.

I know that my measurements were not scientific, nor techie-wise, just plain old eye discerning.

I don't understand why it is so hard to understand that a lens designed to cover a smaller area intrinsically will have more resolving power than one designed to cover 3, 4, 5 and 10 times as much. I don't have a master in physics, but to me it makes sense.

A car stereo, expected to fill a very small area, delivers excellent humph! from very little rms power and technology. Ok, I know it is cliché to compare photography to music, but who can provide a better analogy? - It is not strange that a lot of enthusiast photographers love music, especially jazz.
God made everything. What else is there in the universe for carbon based intelligence?
The experience of light, sound and reproduction.

Eduardo
 
Joseph,

What's this now?
You did make a very definite statement!
Something we could (and did) agree or disagree with.

But now you ask us to believe your statements were "proposals", and that your "evidence" is nothing of the sort, else your "proposals" would be "statements" after all?

And then you go on (!) offering "evidence", for your statement: "I got these evidence after scanning many times. I got the evidence after reading carefully all the Zeiss MTF graphs."
"Good man!"
wink.gif


I too know how 35 mm format and MF lenses perform, and trust me:
"You can indeed examine the results with a loupe, and discover that many 35 mm lenses are even far worse than most MF lenses."

We have discussed the MTF confusion, and though you do persist that they do, MTF graphs do indeed not (!) give the slightest clue about what resolution a lens is capable of.

But you don't except such "evidence", and want to see more.
I don't accept it, your "evidence", either (we have been through it all).
So where's your "evidence", Joseph?

I am not disagreeing for the sake of disagreeing, Joseph...
I'm disagreeing because your assertion does not hold water.
And that's the truth.

And you do say you are interested in the truth.
Yet you evidently do not want to hear it.
Nor offer evidence for, or even stand to your very own version of the truth ("I was not making statements" indeed...
wink.gif
).
 
"I don't understand why it is so hard to understand that a lens designed to cover a smaller area intrinsically will have more resolving power than one designed to cover 3, 4, 5 and 10 times as much. I don't have a master in physics, but to me it makes sense. "

I would believe it is the pinhole effect. In a pinhole camera, if you reduce the size of the hole, you get a darker but clearer picture. It is just like stopping down, you get a clearer image. The same principle applies to the rangefinder lenses and SLR lenses. Rangefinder lenses,being smaller and nearer to the film plane, produces clearer images. Cheers

I will go and find further evidence to prove or disprove what I said.
 
Eduardo,

Ever wondered why the make telescopes so very large?
No, it's not to make them "faster". It is because the smaller they get, the lower their resolving power is. (Google "Dawes limit" fr an explanation.)
That's from the science point of view.
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You ask "why it is so hard to understand that a lens designed to cover a smaller area intrinsically will have more resolving power than one designed to cover 3, 4, 5 and 10 times as much."

The answer is rather simple: that's because it is not so.

Your analogy appears to be based on the assumption that a definite amount of detail is going through a lens, and when it is distributed over a larger area, the resolution, i.e. the amount of detail per area unit, will be less, the detail less dense, than when it only has to cover a smaller area.
That's a nice, elegant, way of looking at it, but alas very wrong!

The diameter of the lens determines how much detail can be resolved.
What the lens does to it, and how much of it 'comes out' at the other end, depends on how good the design, and manufacture, of the particular lens is.
And that's universal: true for all lenses, no matter what format they have to cover.

So the resolving power of a lens depends for a very large part on the effort that is put into correcting all the resolution limiting faults these curved bits of glass introduce.
And that's the deciding factor, the thing that determines which lens is better than another one: how much has been done (and consequently, alas, also how much you will have to pay) to make it so.
 
Joseph,

"I would believe it is the pinhole effect. [...]"

A pinhole 'lens' works by limiting the angle of view.
Think of it as a window, with your eyes being one single, stationary spot somewhere on the recording surface.
When the window is large, your eye sees many things through the window. So the image will be 'confused'.

The smaller the window gets, the less you will see through it.
Until eventually, you can only see a very small part of what's outside, and you will have to move to see the other bits of the scene. Then one spot on the film will only receive light from one 'spot' in the scene. The image will then be much clearer.

Were it not for diffraction, and the extremely long exposure times needed, you could build a perfect imaging system, without any of the lens faults, with an infinitely small hole.


A lens however does have its inherent faults.
While the maximum resolution depends on the diameter of the thing (the bigger the better), lens faults get 'better', i.e. are reduced by restricting the diameter.
So it's a trade off: stopping down will reduce the effect of resolution limiting lens faults, but also the maximal achievable resolution.

At a certain f-stop, the things will be in balance: the effect of the lens faults will not limit the resolution to anything less than the reduced maximum resolution achievable at that f-stop.
Further stopping down will then only increase diffraction and limit the resolution more. (And with diffraction then being the limiting factor, that lens is then 'diffraction limited'. Not always a mark of high quality.).

At what f-stop that will be depends on how well the lens faults have been corrected to begin with. The better the design, the less stopping down will be needed to reduce the resolution limiting effects of lens faults, the less also stopping down itself will limit the lens' resolution.
A perfect lens will be diffraction limited at its widest aperture. And stopping down will always (it's one of those unescapable laws of nature) reduce resolution (approximately halving it every two stops the lens is closed).

So pin holes and stopping down a lens are two very different things.
 
I don't get this continued flood of argumentative words.

The company that makes the stuff says that their MF isn't inferior to the best 35mm in terms of resolving power. Since they also make and sell 35mm lenses of the highest order, why would they publicly say that?

Just curious.
 
> "A pinhole 'lens' works by limiting the angle of view. > Think of it as a window, with your eyes being one single, stationary > spot somewhere on the recording surface. > When the window is large, your eye sees many things through the > window. So the image will be 'confused'. > > The smaller the window gets, the less you will see through it. > Until eventually, you can only see a very small part of what's > outside, and you will have to move to see the other bits of the scene. > Then one spot on the film will only receive light from one 'spot' in > the scene. The image will then be much clearer."

This is not how a pin hole camera works. If you reduce the size of the hole you don't reduce the field of view. You just let in less light.
 
Roh,

I'm sorry, but that's exactly (!) how a pin hole works.

You only get an image because the light reaching one single point on the film can only come from a very limited part of your subject.
The limiting factor is the diameter of the hole, together with the distance between hole and film.
Restricting the angle of view is the begin all end all of pin hole imaging.
 
I am afraid that hi-fi went through the same arguments in favour of perceived quality, rather than objective measurements, and ended up in a totally ridiculous state, where idiots discussed the 'musicality' of different mains electric leads! And ended up with iPods.

There is no reason at all why a lens designed for 35mm should have a higher resolving power than one for MF.
 
"There is no reason at all why a lens designed for 35mm should have a higher resolving power than one for MF"

Correct. No reason why "it should have". It is not a matter of law of physics or mechanics.

Regarding my story of years ago about the comparison between the 4X5 and 35 Nikkor lenses in which the 35 won without doubt:
My friend then excitingly said: "Imagine a 4X5 lens with the resolving power of a 35mm lens!!" - Then a little startled he asked. "Why they don't make them?"

Because they would cost a fortune. We believe it can be done. But can you walk into a camera store and buy a lens that covers 4x5 with more resolving power than one that covers only 24X36mm? - I don't think so. Nasa has one, though.

Hey, look at the new breed of digital "large format" lenses from Schneider and Rodenstock. Their image circles are really small, barely covering 48X37mm. Did these designers decided for the heck of it in favor of a tiny circle over a bigger one to allow for movements? - I don't think so. Although in part is to allow for a little retro-focus design, making them to cover a bigger circle, would call for more sophisticated and more complex design, in consequence making them extremely expensive to manufacture. So they decided for resolving power over coverage.
As usual, a compromise. What isn't in photography.

Eduardo
 
The regular Rodenstock APO Sironar digital lenses do not have very small image circles like the Scheider Digitars. I have two of them (55mm and 90mm) and they are spec'ed-out to cover 125mm. The 90mm even covers 4x5, in my experience shooting it with film. The HR series does have a smaller image circle.
 
Hi,

> > There is no reason at all why a lens designed for 35mm
> > should have a higher resolving power than one for MF

> Correct.

That is not correct as a blanket statement. There is a VERY good reason why larger format lenses are more difficult to design and manufacture than small format lenses of the same focal length and aperture size for fast lenses. The reason is image circle. It is far more difficult to make an 85/1.4 for a 6x6 than it is for 35mm that resolves equally across the entire field covered by that format.

Now, of course, you can reduce the largest aperture significantly and achieve similar resolution results...but that is not comparing apples to apples.

For a focal length/aperture to focal length/aperture comparison, compare the Zeiss 100/2 for Contax, and the Zeiss 110/2 for Hasselblad and you will see they are not even remotely equivelent in resolving power over the image format they are designed for. Or, if that comparison doesn't suit your needs for what ever reason, compare a fast Zeiss 50 (1.2 or 1.4) to an equivelent MF lense giving the same angle of view...an 80mm. How about a Zeiss 35mm 50/1.2 or 50/1.4 vs an 80/...oh, but wait, there is no medium format equivelent for either of these apertures...the best you can get is an 80/2 (Contax and Rollei). How can you compare them then? Might it not be as easy to design either a 50/1.2 or an 80/1.2 (take your pick) for medium format?

So, for fast lenses, I would contend that it is simply not as easy to design equivelent MF lenses. For slower lenses, I won't argue, that's a far easier problem.

Regards,

Austin
 
It's not the image circle, but the angle of view.
Making an 80 mm lens for a larger image circle, that performs equally well as a 40 mm lens for an image circle that is twice as small is not difficult at all.
Making a 20 mm lens for a given image circle that performs equally well as a 40 mm lens for that same image circle is indeed more difficult.

The problem with fast lenses is that they need lots of glass. An f/1.2 80 mm MF lens would be prohibitively expensive.

A comparison between fast 50 mm lenses for 35 mm format and slower 80 mm lenses for MF should not be that difficult, when what you want to compare is their maximum performances.
An f/1.2 lens that performs best at that aperture is rather rare.
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Hi Q.G.,

> It's not the image circle...

It absolutely is the image circle when comparing equivelent focal lengths and apertures between 35mm and medium format (which was what I did, whether you think it's a useful comparison or not is neither here nor there with respect to this fact) and discussing the difficulties in design both lenses in order to achieve the same resolution performance edge to edge for fast lenses.

Comparing two lenses one for each format using the same angle of view is a different problem, which I also addressed. Note, I added "if that comparison doesn't suit your needs" referring to the above, knowing full well that *someone* would bring up comparing equivelent angles of view...which I did address as well. Even in this case, the issue of image circle plays a role as well.

> An f/1.2 80 mm MF lens would be prohibitively expensive.

Yes, but that is becuase of the increased image circle which requires -more- lots of glass for an equivelent aperture lense, not because of the angle of view ;-)

There is increased design difficulty when you make optics "larger" like we are talking about here. You can't just take the same 50/1.4 design and just hit the enlarge button on the copier to make it an 80/1.4. There are some fantastically expensive MF lenses made, so if it was simply expense, I believe we would see some really fast MF glass , clearly people are willing to spend the money. And, BTW, the Contax 80/2.0 isn't a very expensive lense interestingly enough.

Regards,

Austin
 
Austin,

It's not the larger image circle that would make designing a lens that is just as good as one for a smaller image circle more difficult.
It's wanting to keep the focal length the same, and (!) have a larger image circle (i.e. produce a lens with a wider angle of view) that will make it more difficult.

But you're right that it is not simply a matter of scaling up a design (or rather, it is, but then you also have to scale up the effort to keep lens faults from 'scaling up' also).

You're right too about the increased expense of fast lenses for larger formats not being due to angles of view.
I didn't say that it was, only pointed out that expense was the reason you don't get them as much for MF as for smaller formats. ;-)
 
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