Higher contrast = higher resolution?

[RalphLambrecht]

Thanks everyone! @Theo Sulphate
I second your questions Theo! Thats actually something im thinking about too in relation to my original question.
I was originally looking at lithophanes, is that in the same ballpark as your thinking?
Im curious to know if you can etch/emboss in a high dpi/lpmm.
Did you manage this with "compugraphic phototypesetting equipment"? Can you elaborate?

if you look at the offerings from Stouffer stouffer.com You may find what you're looking for but, if you want something hat high a resolution to photograph, just photograph something of lower resolution(such as the USAF1951 target) at from farther away!

 

[jsmoove]

It appears I've gone full circle! (regarding resolving power)

https://www.photrio.com/forum/threa...start-off-as-transparent.177700/#post-2321293

What I'm wondering now is, if putting a lens in front of my smartphone camera, does it change the resolving power of the overall system?
Will a supplemental lens with a "higher resolving power" than my phones lens help to retrieve more data in theory? Or no?

 

[blockend]

Will a supplemental lens with a "higher resolving power" than my phones lens help to retrieve more data in theory? Or no?

Generally speaking, lens resolving power is limited to the weakest link in the optical system. Putting a Leica lens in front of a simple phone optic, will render only as well as the iPhone lens. Some lenses are compound designs where elements are added - supplementary lenses on the Fuji X100 series for example - which are designed with the base formula in mind.

The conditions under which an image is taken affects apparent sharpness, as does editing. For example a textured surface like aging skin or a peeling door, photographed in acute angled lighting such as a setting sun, will optimise any contrast we perceive, whatever the lens. The popularity of the "clarity" editing slider, which exaggerates mid-tone contrast only, allows small, low resolution sensors to produce images that appear to be as sharp as bigger hi-res versions, in normal viewing circumstances. However, given a sufficiently large sensor/negative, resolution is perceptible even in flat lighting. A print of a grey sea on a misty day taken with a 10 x 8" camera printed at 20", will offer almost limitless perceived resolution with minimal contrast.

 

[jsmoove]

@blockend Hey thankyou for the answer. A somewhat related question: adding a supplemental lens, does reducing the minimum focus distance change resolution?

 

[jsmoove]

The other question I have is, if you crop an image with digital zoom, that's a loss of data, correct?

 

[Alan Edward Klein]

So why do images displayed on a smaller TV look better, sharper and more contrasty than the same image on a larger TV screen or print?

 

[MattKing]

So why do images displayed on a smaller TV look better, sharper and more contrasty than the same image on a larger TV screen or print?

Because you tend to sit at a distance that is better suited to the smaller screen than a larger one.

 

[Alan Edward Klein]

Because you tend to sit at a distance that is better suited to the smaller screen than a larger one.

I meant from the same distance. Smaller looks sharper, clearer, with more contrast.

 

[MattKing]

I meant from the same distance. Smaller looks sharper, clearer, with more contrast.

So you are sitting at a distance that is better suited to the smaller screen than the larger one.
|Note that this distance is suited to the sharpness, clarity and contrast. The impact of the image may still be higher from the less sharp, less clear and lower contrast image from the larger screen.

 

[blockend]

I meant from the same distance. Smaller looks sharper, clearer, with more contrast.

A 4k TV is 8 megapixels (8 million pixels overall). Such TVs are often 55-65" in size. If you enlarged a 15 year digital camera image to make a 6ft print, you wouldn't be surprised if the quality was lacking. That's what your typical large screen television outputs - okay from the back of a bar, not good in a domestic setting..

 

[Adrian Bacon]

My curiosity about that leads to these questions:

1. Is it possible to etch on glass or imprint on paper 250 line pairs (or more) per millimeter? I think so, because I worked with Compugraphic phototypesetting equipment which claimed 5000 dpi (fonts and symbols were stored electronically on disk and film was scrolled past a light emitting surface).

2. If (1) is true, what optical limitations prevents those 250 line pairs from being faithfully projected from the source to the sensor? That is my real question.

1: yes. I have a 1951 USAF test target on glass that has down to 900+ lp/mm on it. That being said, 5000dpi is 98 lp/mm (5000 / 25.4) = 196 pixels per mm. You need two pixels per lp, so 196 / 2 = 98 lp/mm.

2. the lens introduces a whole pile of optical aberrations that directly affects resolution. Every glass to air transition affects it. Many lenses don’t focus all the wavelengths to the same plane, which affects it, flare affects it. Diffraction. The lens is by far the weakest link in an optical chain.

 

[grain elevator]

I think there is an aspect to this that hasn't been discussed yet. Many natural objects have infinite low contrast details that do require high contrast to be revealed. Think of leaves or wood grain. Depicted at low contrast, they may seem much more uniform than at higher contrast, when more actual detail is picked up. A white wall may be depicted as a uniform white area in flat light and with a low contrast medium, or as full of tiny details in the uneven surface in directional light with a contrasty medium. So in this sense, more contrast does mean more details resolved, if not more resolution in a strict sense.
Of course it's a question of wehre in the scene details lie. One can also lose details with a high contrast medium if they fall outside the recordable range.

 

[Helge]

I think it needs to be added to Adrians explanation of electronic sensor contrast, that the 100% contrast is purely hypothetical for straight horizontal or vertical lines of the perfect width, aligned perfectly with the sensor sites.
Which never happens.

The second you have real world detail, micro contrast drops dramatically.

This is due to simple, well known sampling gotchas.
Due to the Bayer filter and demosaicing dropping contrast.
Due to readout noise.
And due to the sensor not being the perfect hypothetical platonic “sensor”.

IE. There is well depth, micro lens arrays, hot mirrors, size and shape of the sensor sites, etc. which combined with incidence of light, wavelength and global contrast has various consequences for micro contrast.

For example it might seem neat that digital cameras can record IR with just a filter. But on every shot with any kind of IR (basically all shots) it will lower contrast in general.

 

[Adrian Bacon]

I think it needs to be added to Adrians explanation of electronic sensor contrast, that the 100% contrast is purely hypothetical for straight horizontal or vertical lines of the perfect width, aligned perfectly with the sensor sites.
Which never happens.

absolutely. This is why I said theoretical maximum. In reality, perfect conditions are rarely met.