90 SL cropped to 135mm on a SL2

[bsmith]

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I'm bad with math. When I put my SL90mm on my CL Its a 135mm (approx) on a 24 mp.sensor

If the SL90mm on a SL2 is cropped to the same 135mm view, how many mp is it on  the SL2 ?

Is it the same or does the SL2 have a different mp density sensor ? 

 

[thatkatmat]

From the Manual

APS-C , 5504 x 3664 pixels,  (20 MP)

[Tailwagger]

I don't think the calculation is quite this simple, but roughly as  90mm is 2/3  of 135mm, I'd guess that the number would be somewhere around 32MPx, give or take 1 or 2MPx. 

[happymac]

24,0 / (1,5 *1,5) = 10,67

[Joakim]

12 minutes ago, happymac said:

24,0 / (1,5 *1,5) = 10,67

Almost, the SL2 has a 47 Mpixel sensor so it should be 47 / (1.5 * 1.5) with is 20.9 Pixel

Of course since as stated above the SL2 uses 5504 x 3664 pixels for ASP-C it means it's a 20.2 MPixel sensor

 

Edited September 2, 2020 by Joakim

[happymac]

oh sorry, I assumed the original was 24MP. By the way, the correct formula should be:

8.368/1,5 x 5.584/1,5 = 20.767.516 (20,8 MP)

 

 

 

[bsmith]

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So a SL lens on a CL is always higher resolution (at its CL APS   "cropped" value) , than if used on a SL2 and cropped to the same CL APS  focal length  size?

Doesn't this mean that a CL has a higher resolution sensor than the SL2?   Seems strange, why wouldn't Leica use the (CL) sensor in the SL2. Wouldn't the SL2 be then a +50 mp camera?

[Joakim]

I don't know much about the CL but it is a couple of years older than the SL2 so the sensor must be, at least, a couple of years older than the SL2 so even if a FF version of the CL existed Leica might have wanted to use a newer sensor and also I have no idea if it is the same manufacturer.

 

[Eclectic Man]

According to the SL2 manual, page 86, the DNG resolution for APS-C images is 20 MP.  The Resolution of the APS-C CL is 24 MP. So the CL has a physically smaller, but higher resolution sensor than the SL2.

On 9/2/2020 at 9:50 PM, bsmith said:

So a SL lens on a CL is always higher resolution (at its CL APS   "cropped" value) , than if used on a SL2 and cropped to the same CL APS  focal length  size?

Doesn't this mean that a CL has a higher resolution sensor than the SL2?   Seems strange, why wouldn't Leica use the (CL) sensor in the SL2. Wouldn't the SL2 be then a +50 mp camera?

Actually if you consider the physical sizes of sensors and the number of pixels in a typical mobile phone, a 100 MP FF sensor is quite easy to make.  The problems are not resolution, but avoiding dead pixels, controlling noise and interference, and the heat generated by powering it, and, of course the time required to read the data.  Over a year ago there was a rumour Canon intended to bring out a 100 MP FF camera, what we got was the 45 MP R5 (no relation to the classic Leica R5 SLR, of which I am a proud owner).

[Jared]

Usually, one would say that the CL has a smaller pixel pitch than the SL2 rather than saying it is a higher resolution sensor. Traditionally, resolution could be quoted in one of two ways, either line pairs per millimeter or line pairs per picture height. The former works well when comparing lenses or sensors within a given format. The latter approach is more universal and describes resolution across an entire image regardless of format. The CL would likely win in a “line pairs per millimeter” contest over the SL2, but would lose in terms of “line pairs per picture height”. If you just say it has a finer or smaller pixel pitch—space between pixels—you are removing any confusion over which measure of resolution you are talking about.

Just as an example, an iPhone has a pixel pitch of about one micron, depending on which camera/lens combo you are using. A 24 megapixel APS-C sensor like that in the CL has about 3.9 micron pixels. The SL2 has 4.2 micron pixels. The SL has 6 micron pixels. I don’t think anyone would suggest an iPhone has 4x the resolution of an SL2. The resolution in an image is not determined by pixel pitch alone. The size of the sensor also matters as well as the quality of the lens being used. That least one can get pretty tricky as well. There is more than one way to measure lens quality, and some measures are easier to achieve with smaller formats while others are easier to achieve with larger.

In any event, chip yields tend to fall off with larger megapixel counts, not with smaller pixel pitches. So making a 100 megapixel full frame chip is actually quite expensive even though the “resolution” of the pixels would be lower than in an iPhone.

[Eclectic Man]

As an aside, see: https://www.independent.co.uk/life-style/gadgets-and-tech/space-telescope-vera-c-rubin-observatory-broccoli-photograph-biggest-ever-b420934.html 

Photograph taken using a 3.2 Billion pixel sensor, but don't expect one in a camera you can buy too soon.

[jaapv]

5 minutes ago, Eclectic Man said:

As an aside, see: https://www.independent.co.uk/life-style/gadgets-and-tech/space-telescope-vera-c-rubin-observatory-broccoli-photograph-biggest-ever-b420934.html 

Photograph taken using a 3.2 Billion pixel sensor, but don't expect one in a camera you can buy too soon.

Not only that - they used a pinhole lens.