[swanlefitte]

I'm sorry, you're just dead wrong. How can there possibly be "less pixels making it onto the print (or monitor)"?

Not dead wrong. Just confusion. A smaller pixel tasked with gathering the same information as a larger one won't gather as much and have more noise. Less pixels printed at 200 dpi to be the same size as more pixels at 300 dpi will look worse. This has to do with the sensor and print size and not the lens though. Print small pixels smaller or print less pixels at 300 dpi and have a smaller picture and quality is the same. Tony N fails to mention that part.

[pschlute]

but I think a good approximation for the resolution of the optical system would be the sum of inverses (analogous to the total resistance of resistors in parallel;


.. but I think you would agree that we could define a pair of pixels as an inverse of the spatial frequency where contrast drops to 50% of its low frequency value (I did not invent this; this is how Line Pairs per Picture Height is determined).

Did you notice you also lose light flux as well when using an FF-lens on a cropped sensor? Full-frame FA 35/2.0 performs as a 53/3.0 lens on the APS-C sensor.

No, you are accurately describing how a lawn-mower works, not a lens/camera combination.

Since I upgraded to a Full Frame lawn mower I get much improved contrast in my "stripes", plus of course a narrower depth to my field.

...

Bottom line, it's too complicated to think about, to complicated to understand. Look at your images and decide if they re good enough. If not look for something you might find more pleasing. But whether that will a one inch sensor, micro 4/3, APS-c or FF, you won't figure it out with math. To many variables and too much personal preference. But all those sensors can produce images in the 2600-4000 range. That is good enough for 26 x __ inch print at 100 distinct lines per inch or more, which is darn good.
...

Good explanation, and to sort of echo that, I'd say that the bottom line is that there's no disadvantage to using a full-frame lens on an APS-C body; to the extent there's any drop in image quality, it's because of the body, not the lens.

[normhead]

Oh my goodness, did we get jumped by another Northrup acolyte?

It's been so long since it's happened I didn't recognize it. But it's been years since I read his stuff. Is this his new tangent? Wasted pixels?

I feel like a janitor when someone gets in love with his narratives. He's created this huge mess. Forums like this end up trying to clean it up. As soon as you let your guard down.

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Last edited by normhead; 02-13-2021 at 07:00 PM.

[pschlute]

Oh my goodness, did we get jumped by another Northrup acolyte?

It's been so long since it's happened I didn't recognize it. But it's been years since I read his stuff. Is this his new tangent? Wasted pixels?

I feel like a janitor when somoe gets in love with his dome. He's created this huge mess. Forums like this end up trying to clean it up. As soon as you let your guard down. D

I always use one of these to sweep up all the spilled pixels if I use a FF lens on aps-c

[normhead]

It's odd to have to say it, but, don't believe everything you read on the internet.

[Lowell Goudge]

I am into this thread a little late but it seems we are , to quote an old children’s poem/song playing a game of “apples, peaches, pears and plums”

After browsing the thread, we are mixing lens resolution, sensor pixel density, image circle, and crop factor.

So, I will throw all that in the garbage, and start fresh.

Lens resolution is independent of sensor, and crop factor, resolution is purely a function of the lens, BUT unfortunately, we judge resolution with the sensors in our camera and throw an uncontrollable variable into the equation.

Similarly comparing edge resolution between the same lens on crop and full frame sensors is wrong, because you are measuring in a different part of the image circle of the lens.

If we go back to the simple question of FF on crop sensor bodies, the only negative I can see, is that a cropped sensor lens, may have baffles that prevent light beyond the frame from exiting the lens, if this is the case, then there may be an improvement in contrast, because, stray light bouncing around in the mirror box could ultimately find the sensor, and produce a slight fogging or lack of contrast.

A bigger issue, is many FF lenses for Pentax were film cameras and some of these may not be designed to deal with reflections off the sensor, an all to common issue unfortunately

That has nothing to do with full frame vs crop but more film vs digital coatings

[normhead]

There are lots of maybe's and undetermined probabilities, none of which have been empirically shown to exist. With the 35 2.4 and 55 1.4 Pentax released lenses that are fully full frame compatible without baffles, so they clearly didn't buy into the possibilities. No one has complained removing the baffle degraded the images from the 60-250 when shooing on APS-c.

The baffle in the 60-250 is as far as I'm concerned a tribute to too much worry about an unconfirmed effect. It's notable they never repeated it. They probably discovered it didn't really do much but cripple the lens.

There is simply no empirical evidence to suggest there is a performance difference.when FF lenses are used on APS_c cameras, or even 4/3 cameras where theoretically the problem would be worse.

[Thagomizer]

It's odd to have to say it, but, don't believe everything you read on the internet.

I believe Abraham Lincoln said that. On the internet...

[Lowell Goudge]

There are lots of maybe's and undetermined probabilities, none of which have been empirically shown to exist. With the 35 2.4 and 55 1.4 Pentax released lenses that are fully full frame compatible without baffles, so they clearly didn't buy into the possibilities. No one has complained removing the baffle degraded the images from the 60-250 when shooing on APS-c.

The baffle in the 60-250 is as far as I'm concerned a tribute to too much worry about an unconfirmed effect. It's notable they never repeated it. They probably discovered it didn't really do much but cripple the lens.

There is simply no empirical evidence to suggest there is a performance difference.when FF lenses are used on APS_c cameras, or even 4/3 cameras where theoretically the problem would be worse.

I agree.
It’s a carry over from the film era. My K300/4 has a similar rectangular baffle. I think the 100/4 macro also. But I have not looked in a very long time at the back of the lens, I am more concerned about what I see through it, not in it.

[normhead]

I believe Abraham Lincoln said that. On the internet...

That's like " I read a study that said 60% of studies have conclusions not supported by their data."

I actually did read that once. The question that comes to mind being, how do I know this isn't one of those studies that's made a conclusion not supported by the data.

[Lowell Goudge]

That's like " I read a study that said 60% of studies have conclusions not supported by their data."

I am a fan of Murphy’s laws, and one of then states, “given enough data you can prove anything with statistics”

Edit note, actually holland’s law

[mbukal]

I read somewhere (on the net) when the question was asked: if the FF lenses on the APSC format are sharper throughout the frame whether this is true for 645 lenses on the FF, it is said that it is not valid and that it is not worth adapting the 645 lens on the FF greater sharpness is expected throughout the frame

[stevebrot]

Since I upgraded to a Full Frame lawn mower I get much improved contrast in my "stripes", plus of course a narrower depth to my field.

Dang! That's a good one. You should put it in your signature.


Steve

[revelstoked]

"Pixels" are not projected on the sensor. Pixels are the output of the individual photoreceptors on a sensor. The main difference in using FF vs APSC lenses is the internal image projection is of a larger diameter when using a FF lense (to accomodate the large sensor size.) This means, on APSC that you are not capturing everything that the lense is capable of "seeing" as the outer edges are being projected beyond the edge of the sensor. Conversely, when using APSC lenses on a FF body, the projection diameter can be too small for the size of the sensor, leading to circular fringes. Resolution of the projected area is unaffected in either case as it is a function of the sensors sensitivity and pixel density, and also the overall quality of the lense in question.