D60's ( APS-C )sensor is too small to stop down below f/11?

Adding pixels without simultaneously increasing the sensor size will indeed give you more detail until the sensor becomes diffraction-limited at the apertures available on the lenses used with that sensor. Most high-density digicams are equipped with lenses that possess apertures far smaller than necessary to induce "visible" degredation in a 300 ppi print viewed at a distance of 10 inches with eye balls capable of resolving only 5 lp/mm. It is impossible to resolve 5 lp/mm in a 300 ppi print if diffraction's Airy disks are limiting detail to something less than 5 lp/mm.

Mike Davis

If this were true, manufacturers of expensive DSLR's and MF backs would already be offering sensors with densities higher than 188 pixels/mm. It's not as if the manufacturers of high-density digicams know something the DSLR manufacturers don't know. Canon (and other companies) offer products on both sides of the pixel density gap. Canon understands that diffraction inhibits detail - that high density sensors are compromised by diffraction at all but their widest apertures when making 300 ppi prints to be viewed at a distance of 10 inches - that additional detail can NOT be had at "whatever the aperture" just by adding more pixels to a sensor of a given size.

Mike Davis

It's not possible to not put some degree of spin on something. We're not automata, are we? Everything has to be interpreted. From the above statement, I got the impression you are using this evidence of a gap, in the progression of pixel sizes, to support a notion that pixel sizes within this gap are avoided by camera makers because of some inherent DoF disadvantage of those sizes.

We've already been through this. According to resolution tests at Dpreview, no digital cameras currently available with fewer than around 12mp are able to resolve 5 lp/mm in a 300 ppi 8x10 print, whatever aperture is used, however good the lens, whatever distance the print is viewed from and whatever the acuity of the viewer's eyesight.

However, I notice you have now dropped off the mention of print size, and very sensibly too, so don't get back to me and accuse me of misinterpreting your statements. You've mentioned the print size in previous posts.

As it stands, outside of the context of your previous posts, your above statement is essentially true. It's a pretty obvious statement of fact that diffraction limits the resolution of all cameras of all types. We could substitute the beginning phrase, "Most high-density digicams....", with "Most cameras, whatever the format...", and your statement would still be true.

An 8x10 large format field camera is also equipped with a lens that possess apertures far smaller than necessary to induce "visible" degredation in a 300 ppi print viewed at a distance of 10 inches with eye balls capable of resolving only 5 lp/mm. It depends on what aperture you use and what size print we are talking about.

Without spending time collecting data and doing calculations, I would hesitate to specify a precise aperture and print size at which the above conditions are fulfilled for an 8x10" LF camera. There are so many variables, including the MTF response of the film used, but I would confidently predict that any really large print of around 4ftx5ft would not deliver 5 lp/mm viewed from 10 inches if the aperture used to take the shot was, say f90.

OK. I don't see anything about DoF in the text accompanying the graphic or in my post that introduced the graphic, but I'll take you at face value. You simply didn't understand it.

http://home.globalcros​sing.net/~zilc...Densi​tyGap.jpg

Have today's posts helped you to understand "my" interpretation?

Mike Davis

You're misinterpreting my statements. I've not abandoned the mention of print size. Throughout this entire thread, I've repeatedly indicated that for the sake of making fair comparisons, the print sizes vary from one sensor to the next, having "normalized" them to those dimensions had at 300 ppi. So if the sensor offers maximum pixel dimensions of 2400 x 3000 pixels, the resulting print dimensions at 300 ppi would be 8 x 10 inches.

I'll continue to spell it out for you over and over and over again, if that's what it takes to discourage your misinterpretations. You write about how we've been through "all this" before, but in my opinion, your arguments exhibit a failure to remember the details of this thread in addition to a failure to understand what I've written in the first place.

Mike Davis

Mike,
Your argument is not sound. There are many technological reasons why Canon has not to date given us greater pixel density than that of the 20D and 30D. Foremost amongst these would be noise. After Canon introduced its first DSLR, the D30, every subsequent model has produced either the same amount of noise, at equivalent ISO, or less noise. It's simply not Canon's policy to go backwards on this important issue of noise. A low noise, high ISO camera is a tremendous asset to the photographer.

The Nikon D2X is an example of the sort of performance one might expect if Canon were to cram more pixels on an upgrade to the 20D. Resolution would equal that of the 5D, but at this stage of development, it is a fair assumption that the technology is not quite there to keep noise levels within Canon's historic standard. The D2X (without use of detail destroying noise filters) has more noise at high ISOs than any of Canon's current DSLRs. The pixel density of the D2X would equate to that of a 28mp full frame 35mm DSLR. I would expect that some time in the future Canon will give us such a camera which will have noise levels at least as good as the current 5D or 1Ds2.

In the meantime, one would hope that lenses will improve to take better advantage of such increased sensor resolution. The fact that the D2X is on a par, resolution-wise, with the 1Ds and 5D would indicate that some Nikkor lenses are already good enough, in the central area at least.

Would you have us believe that a low-density DSLR sensor (ie: 139 pixels/mm EOS 1Ds Mark II) is every bit as diffraction-limited across its range of available apertures as a high-density digicam sensor (ie: 535 pixels/mm Sony DSC-H5) is across its range of available apertures?

Yes or No?

Please begin your response with a simple "Yes" or "No". Anything else might be interpreted as intentionally ambiguous.

Mike Davis

Wow. You write as if there was no yesterday and no tomorrow. You exhibit no retention of things just said. The very graphic we are debating at the moment speaks of the vulnerablity to both diffraction AND NOISE had with increased pixel density. Do you have a bad memory or are you just hoping that everyone else does?

Mike Davis

No. I don't have a particularly bad memory and nor do I substitute clear argument for rudeness and personal abuse.

No! Diffraction limitation of lenses is a property of lenses. Nothing to do with sensors or pixel density. The issue is, can the sensor capture what the lens delivers? Both low density and high density sensors can capture low resolutions. The higher the pixel density, the greater is the potential of the sensor to capture every detail the lens is able to deliver.

I'll add to that to make it clearer. The higher the pixel density, the greater the potential of the sensor to capture all the detail the lens is able to deliver at any specified f stop, irrespective of whether the lens is diffraction limited at the specified f stop.

Question:

Answer:

Thank you! With a single word, you've proven to anyone who understands the impact that pixel density has on enlargement factor and thus, on the diameter of Airy disks in the final print and thus, on the ability to resolve detail in the final print, that you really, truly just don't get it. I apologize for thinking otherwise.

If there's anyone else out there willing to join Rayz in answering this question with a resounding "No!", please jump in and make yourself known. I'm sure he'd appreciate your support.

The defense rests.

Mike Davis

---------------

Rayz, I'm adding this comment in "edit" mode after you made your post, below. When I wrote the text above, I had just read your entire response to my question, which begins as follows: "No! Diffraction limitation of lenses is a property of lenses. Nothing to do with sensors or pixel density." In retrospect, I've realized that your response, as a whole, supports a "Yes" answer to my question. That is how I heard it and that is how I responded to it, despite your having transposed the word "No" for the word "Yes". Had I noticed the transposition before making this post, I would have pronounced your reply as self-contradictory.

If you read the question carefully, you'll see that a "No!" answer actually agrees with my position. A "Yes!" answer is appropriate if you disagree. Please revisit the question and make it clear whether your answer is "Yes" or "No."

I'm fairly certain the bulk of your response to my question is saying: "Yes! I would have you believe that a low-density DSLR sensor is every bit as diffraction-limited across its range of available apertures as a high-density digicam sensor is across its range of available apertures."

On the assumption that you really meant to answer the question with a "Yes!", the following paragraph of my response should have read, as follows:

---
If there's anyone else out there willing to join Rayz in answering this question with a resounding "Yes!", please jump in and make yourself known. I'm sure he'd appreciate your support.
---

Are we having a hard time communicating, or what?

Mike Davis

It seems that Mike is trapped in an Aristotelian world of 'either/or'. He thinks that a lens is either diffraction limited or it isn't. He wants simple 'Yes' or 'No' answers. He doesn't seems to realise that lenses move from a state of being mostly aberration limited to mostly diffraction limited over a number of f stops.

I do not think "a lens is either diffraction limited or it isn't."

I do realize "that lenses move from a state of being mostly aberration lmited to mostly diffraction limited of a number of f stops."

Mike Davis

Mike,
The question, 'yes' or 'no' seems confused to me, hence my contradictory answer. This is the sort of technique that is often used when people conduct polls. They want yes or no answers to questions that are best answered with neither yes nor no.

I simply don't believe that sensors have anything to do with diffraction in lenses. The sensor simply attempts to record whatever the lens delivers to it, including all types of aberrations and Airy Disks. More pixels are generally better than fewer pixels and that is the trend we see in successive models of digital cameras. Noise is a technological hurdle which is gradually being overcome, but of course there are always limits to what can be achieved.