# Cross platform equivalency

Started 8 months ago | Discussions thread
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 I am Spartacus! In reply to Silverback1988, 8 months ago

Silverback1988 wrote:

qianp2k wrote:

I am sorry Peter, try this link :

https://www.dropbox.com/s/kppr1f7pnab4r5v/IMG_3423.JPG

It should work. If not, just consider I have low threshold on sharpness

Say, do you happen to have her email? There's a question I need to ask her...

Happy is relative and respective during specific time period. People happy on B&W TV during that time, people happy on color TV later, people happy on CRT TV then and happy on LED HD TV now. When 4K monitor get popular and cheap and eventually 8K monitor another 5-10 yrs later, you'd be happier with 36mp or more resolution.

You are right, that means now we are difficult (or can not) to be happy just CRT TV.

Honesty, I remember that I was happier when I got my first digital camera (Kodak 2 MP) rather than when I got my first FF (5DII). I don't know if I will happy at all if I got my first MF

The other extremely important variable that people rarely mention are:

• Display Size
• Viewing Distance
• Visual Acuity

These three variables go a long way to answering the question, "How much resolution is enough?"

BTW, I see your another thread. In thumb of rule, larger sensor better IQ, better sharpness and resolution. 50mp MF > 50mp FF > 50mp APS-C > 50mp mFT > 50mp 1" provided sensors have the same QE (quantum efficiency)

And also provided that the lenses for the smaller formats are not sharper by a factor of the equivalence ration and/or have less pixels.

Yes, I could understand that logic.

For example, 24 MP mFT will resolve just as well as 24 MP FF if the lens is twice as sharp.

Why? Simple because larger sensor, less enlargement in pixels when project to output at the same size, so-called crop factor or crop penalty.

Assuming the lens is not outresolved by the sensor, do you think the smaller one still can keep up with the larger one (for the resolution or sharpness) ?

Yes, depending on the particular lenses being compared.

For example, imagine a lens is designed that could record 6000 dot in 35mm linear and both can be used on any sensor.

Actually, it doesn't work like that. Putting more pixels behind *any* lens increases resolution. How much more resolution depends, of course, on the sources of blur which include:

• The sharpness of the lens
• Motion
• Shake
• DOF
• Diffraction

With 35 FF sensor area, it will record 6000 x 4000 dot (or 24 MP worth of data)

With mFT sensor area, the sensor will use 25% of the lens, so it will record 3000 x 2000 dot (or 6 MP worth of data)

WHAT IF ... both sensors (FF & mFT) have only 6 MP sensor ???

Both ended up with only 3000 x 2000 dot recorded, thus has the same resolution, no ?

Let's say we had an infinitely sharp lens. Then it would resolve the same detail at the same DOF on any format that had the same number of pixels and AA filter.

However, if we are using lenses with the around the same sharpness on different formats, then the larger formats will almost invariably resolve more detail due to the enlargement factor, although, at times, the greater pixel count of a smaller sensor over the larger sensor (e.g. 24 MP APS-C over 12 MP FF) can narrow, or reverse, the gap.

By the way, these two places in the frame from DPR's comparison tool:

http://www.dpreview.com/reviews/image-comparison?attr18=daylight&attr13_0=canon_eos6d&attr13_1=canon_eos70d&attr13_2=oly_em1&attr13_3=nikon_df&attr15_0=raw&attr15_1=raw&attr15_2=raw&attr15_3=raw&attr16_0=100&attr16_1=100&attr16_2=100&attr16_3=100&normalization=full&widget=1&x=-0.10321931589537224&y=0.3274263187535198

http://www.dpreview.com/reviews/image-comparison?attr18=daylight&attr13_0=canon_eos6d&attr13_1=canon_eos70d&attr13_2=oly_em1&attr13_3=nikon_df&attr15_0=raw&attr15_1=raw&attr15_2=raw&attr15_3=raw&attr16_0=100&attr16_1=100&attr16_2=100&attr16_3=100&normalization=full&widget=1&x=0.3483651911468813&y=-0.07062136286840623

give, in my opinion, a good visual reference for the max differences in detail you may find as a function of format and pixel count.

The 6D and 70D have almost the same pixel count, so you can see the effect of the enlargement factor at work.  The Nikon Df has a lower pixel count on a larger format, so you can see how the enlargement factor and pixel count relate compared to a smaller format.

Also, if you switch one of the cameras between the D800 and D800E, you can see the resolution advantage of more pixels on a larger format, as well as the effect the AA filter can have.

Of course, the DPR studio scene shows the differences in resolution under idea conditions.  In peoples' everyday shooting, one might expect to see much smaller differences.

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