Comparing lens resolutions

[pjbw]

It looks as if a recently announced camera might supplant my 2005 one (don't laugh!) both with fixed lenses.
However I would be disappointed if I paid out £1000 to find it was no or only minimally better.
Reviews of the new camera include its 'Live Widths per Picture Height x 100'.
This may not be a relevant comparison; my old camera is 10.3 MP, the new one 20 MP. However if it is maybe someone could tell me how to measure this for my old camera; is there software?

[Shadowman]

It looks as if a recently announced camera might supplant my 2005 one (don't laugh!) both with fixed lenses.
However I would be disappointed if I paid out £1000 to find it was no or only minimally better.
Reviews of the new camera include its 'Live Widths per Picture Height x 100'.
This may not be a relevant comparison; my old camera is 10.3 MP, the new one 20 MP. However if it is maybe someone could tell me how to measure this for my old camera; is there software?

Is it one of those with the vintage design?

[pjbw]

Is it one of those with the vintage design?

'vintage design?' ?

[Black Pearl]

You might want to give us a little more to go on - like - what camera you're on about, what you have now, what lens you will be using it on, what you mainly use it for, what improvements you're hoping for.....that should do for starters and give us a fighting chance.

[xpatUSA]

It looks as if a recently announced camera might supplant my 2005 one (don't laugh!) both with fixed lenses.
However I would be disappointed if I paid out £1000 to find it was no or only minimally better.
Reviews of the new camera include its 'Live Widths per Picture Height x 100'.
This may not be a relevant comparison; my old camera is 10.3 MP, the new one 20 MP.

Line widths per picture height is convenient and meaningful for some.

To compare two cameras with fixed lenses more precisely, I would prefer to find out the sensor heights in mm and then work out the line pairs/mm.

For example, my micro 4/3" sensor is 13mm tall. At 12.1MP, the max possible res (google Nyquist limit) is 1500 lp/picture height = 115.4 lp/mm. A DPReview test has the actual res measured 1150 lp/picture height which comes to 88.5 lp/mm. My SD10 sensor is 13.8mm tall. It's max possible res is 756 lp/mm = 54.8 lp/mm. (DPReview's test for the SD10 is invalid because it shows a slightly higher resolution than the max possible).

If, on the other hand, both cameras are APS-C, then the figures you have can be compared directly. In that case, it is likely that the 20MP will show better spatial resolution in terms of lp/mm but not twice as good.

However if it is maybe someone could tell me how to measure this for my old camera; is there software?

If by 'this' you mean spatial resolution you will need to obtain a test target of some sort, perhaps the ISO one, learn how to use it and do the test yourself. Or have a look at the DPRreview camera reviews and find your model. They do publish test results but beware their per picture height numbers. They are in lines, not line pairs.

http://www.dpreview.com/camerareviews

People who print find absolute spatial resolution more important than those who publish only to the web or their TV. Downsizing images to e.g. 960px wide on your monitor is a great leveler, IMHO

[Manfred M]

Frankly with a camera from 2005 versus a current one, I would not get too concerned with lens resolution (which will have improved). The biggest change that you will see is the improvement in sensor technology; dynamic range, noise performance and colour depth have improved leaps and bounds.

Yes, lens technology has moved on as well, but the other improvements are going to result in much more significant and tangible improvements in image quality.

[ajohnw]

Yes you can buy software and kit to make the measurements.from here

http://www.imatest.com/docs/sfr_mtfplot/

If you google slant edge test you will probably find DIY approaches and loads of info. It's a hot topic. This page gives some drawbacks, another is the need for a very accurate focus. Then comes at what distance as mentioned in this

http://bvdwolf.home.xs4all.nl/main/f...antedEdge.html

Best way to find out about the resolution of any kit some one may own is to download and print some test charts from this site

http://www.normankoren.com/Tutorials/MTF5.html

USAF resolution targets can be found too and may be more suitable for testing a telephoto at it's usual working distance.

Line Widths per picture height relate to the size of the sensor and I assume mean lines without and spaces as it would give bigger numbers. Just a guess. You could relate that to pixel pitch on a given sensor and see if there are any gains remembering that cameras use blocks of 4 pixels to obtain colour information. Those are scaled according to intended colour and interpolated which complicates things related to the use of individual pixels for calculations. No idea how they get round that.

Personally I think the reviews done this way are a useful guide but I'm not convinced they entirely relate to reality. Test charts at suitable distances are more reliable. I haven't done any for years and years. Magazines used to give the charts away.

John
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[Glenn NK]

However if it is maybe someone could tell me how to measure this for my old camera; is there software?

Peter:

The tests have been done for many lenses:

http://www.photozone.de/all-tests

Select your format/brand, then select from the list of lenses.

Glenn

[Shadowman]

'vintage design?' ?

Similar to these in link.

http://www.togtech.com/5-must-have-r...gital-cameras/

[xpatUSA]

Peter,

With reference to slant-edge testing, mentioned by John earlier, the results should be interpreted with care. I have 'QuickMTF' and have done many such tests. A problem arises when comparing camera/lenses with different pixel sizes (pitches actually). The 'goodness' of the combination, i.e., the MTF, is presented on a per-pixel basis - and sensors with big pixels can score better in a slant-edge test than those with smaller pixels.

Let's say we get an MTF of 50% at 'only' 0.25 cy/px on my GH1, but at a whopping 0.33 cy/px on my SD10. Which score is 'better'? Taking 'cy' as meaning a line pair (not quite true but good enough for this exercise) we get:

0.25lp/px * 3000px/13mm = 57.69 lp/mm for an MTF of 50% on the GH1 (px's cancel out)
0.33 * 1512/13.8 = 36.16 lp/mm for an MTF of 50% on the SD10.

QED, the GH1 is 'better' than the SD10, even tho' the test figures implied the converse.

[GrahamS]

Peter, I would not worry about comparing the MTF test results of two fixed lens cameras. I suggest that it is the image quality in practical use that you should compare, and to do so I would try and find test reviews of the cameras on line, at sites such as this: http://www.dpreview.com/

[ajohnw]

The photographyblog site is good for comparing cameras. They provide full res images and raw files which can be downloaded if the camera can produce them.

One thing I will add assuming this relates to a small sensor camera I have seen some evidence that cameras that shoot full HD showed an improvement in the optical quality of the lens over pre HD cameras. That's on compacts. May well be similar on bridge. On the other hand I have a truly ancient original digital Ixus with just 2mp. In practice it resolves more detail then the 5mp+ version. This sort of effect can be seen by blowing a shot up to full size. Depends on the camera but some will show a rather fuzzy image that only looks any good when it's reduced in size. Sometime the main loss of detail is in the background of the shot. No idea how they manage that on jpg only cameras but I have seen some where they do. Cameras that produce raw images can tend to be better but often some of the detail in the shot is wishy washy at 100% view. There are clearly too many pixels for the optics on some.

John
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[pjbw]

You might want to give us a little more to go on -

Apologies for this late reply - Christmas! At this stage I want to keep things as objective as possible. I won't go further than to say that my 2005 camera has achieved 'legendary' status with some current reviewers.

[pjbw]

People who print find absolute spatial resolution more important than those who publish only to the web or their TV. Downsizing images to e.g. 960px wide on your monitor is a great leveler, IMHO

Apologies for late reply - Christmas! I think it is important for me not to get sidetracked by the DSLR brigade with their interchangeable lenses. I want to compare lens-sensor combinations. At the moment I prepare nominally 12" x 8" prints for exhibitions at 300 DPI ( the biggest I can do at 10.3 MP) with my 'old' camera. These are fully comparable with similar prints from megabucks Canons and Nikons.
Unfortunately the DPReview while the review was so good that I went ahead and bought the camera in 2006 there weren't any tests that I could use to compare with modern reviews.
I will look at the ISO test target but will need to find published results for the new camera.

[xpatUSA]

I want to compare lens-sensor combinations. At the moment I prepare nominally 12" x 8" prints for exhibitions at 300 DPI ( the biggest I can do at 10.3 MP) with my 'old' camera.
Unfortunately the DPReview while the review was so good that I went ahead and bought the camera in 2006 there weren't any tests that I could use to compare with modern reviews.
I will look at the ISO test target but will need to find published results for the new camera.

It would be quite helpful to know what these 'old' and 'new' cameras are! No need to be coy - look at the junk I shoot with, for example . . .

[Black Pearl]

Apologies for this late reply - Christmas! At this stage I want to keep things as objective as possible. I won't go further than to say that my 2005 camera has achieved 'legendary' status with some current reviewers.

I give up.

We could go round in circles for the next month only to find the incredible advice and experience available here has been wasted by not having even the most basic information.

Good luck in whatever you buy and have a Happy New Year.
Robin

[pjbw]

I give up..Robin

Ok, I give in!
My old camera is the Sony DSC-R1. It may be replaceable with the new Sony RX10.
There is no urgency. When the R1 was discontinued and the price dropped I bought a spare.
I have no need for video, stabililsation, wi-fi, etc, etc but the 20MP would be very nice and usable RAW (Sony's 2005 SR2 is no improvement on their JPEG with Adobe RGB (1998)),PROVIDED there is NO reduction in quality of my photos.
As yet there isn't a DPReview of the RX10 so I can wait.
In the meantime I will work through the suggestions in this thread; thank you all very much. Peter.

[xpatUSA]

http://www.techradar.com/reviews/cam...articleContent

http://www.imaging-resource.com/came...ony-rx10A4.HTM

Would comment that the R1, although older, has an APS-C size sensor but the RX10 has a 1" (half the size, 1/4 the area). BSI though.

In your position, I would consider micro four thirds with it's choice of lenses. I don't see how an 8x zoom can be good at all lengths but it is a Zeiss, I guess.

[ajohnw]

You probably are better off waiting for a dpreview.

I can't see it matching up to your current camera though. A 1in sensor and super zoom optics against APS and a very good lens.

I think if I wanted a camera with a 1in sensor I would look at the Nikon 1's. There are dpreviews on those which should give you some idea.

John
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[ajohnw]

You can download images taken with both cameras here.

http://www.ephotozine.com/site-search/sony-rx10

John
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