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03-09-2016, 01:35 PM   #1
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View finder size comparison

When I looked through the K-1 viewfinder I didn't think it was sooo much larger than the one in my K5. Back at home I compared the K5 with my Super A (Super Program in the US) and perceived a huge difference. So I made a drawing in InDesign to find out. The size on your screen will depend on your screen resolution, but you can easily see "real life" size by making the black rectangle 36X24 mm.

Black= true FF sensor size
Red = Super A viewfinder size
Green = K-1 viewfinder size
Blue = K5 viewfinder size

Name:  Sensor sizes.jpg
Views: 729
Size:  19.2 KB

Side note: I did check the 645Z. Sensor size 43,8mm X 32,8mm, coverage 98%.
But — the reduction varies with lens, e.g. 0.62x with 55mm lens, 0.85 with 75mm lens. Can someone explain this?

Kjell


Last edited by bilybianca; 03-09-2016 at 01:43 PM.
03-09-2016, 01:47 PM   #2
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really?! K1 and k5 are that close in size? why the eyecup so much bigger on K1?

K5: sensor 23.6mm. 23.6mm x 92% = 21.7mm
K1: sensor 36mm. 36mm x 70% = 25.2mm

-- they are not that much different indeed! But the difference should be bigger than shown in the figure above?

Last edited by grahame; 03-09-2016 at 02:08 PM.
03-09-2016, 02:36 PM - 3 Likes   #3
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Hi Kjell,
The virtual size of the viewfinder display is not directly related to the format size, but is based on the magnification relative to 50mm FOV (arbitrary standard)*. As such a FF viewfinder with 100% coverage at 1x magnification will have a diagonal 1.5x that of an APS-C viewfinder having 100% coverage at 1x magnification. The two will appear the same size if the FF viewfinder has 0.67 magnification or if the APS-C had 1.5x.

A real world example:

K-5 viewfinder is 100% coverage with 0.92x magnification
K-3 viewfinder is 100% coverage with 0.97x magnification
K-1 viewfinder is 100% coverage with 0.7x magnification

The K-1 viewfinder will appear a little larger than that of the K-3 and a notch more than the K-5. This is decent, but a notch off the Super Program (92% at 0.82x). Your diagram shows this nicely. FWIW, the ME Super is 92% at 0.95x and would appear significantly larger than the K-1.

Added: A bit of trivia...a 1x viewfinder may be used with both eyes open since the magnification is the same as unaided eye. With rangefinder cameras having such (rare), this is a distinct advantage in that it allows the photographer use of their peripheral vision.


Steve

* Why the same is applied to both FF and APS-C is beyond me. Regardless, the key is to think in terms of degrees of arc for the diagonal.

Last edited by stevebrot; 03-09-2016 at 03:05 PM.
03-09-2016, 04:16 PM   #4
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QuoteOriginally posted by stevebrot Quote
Hi Kjell,
The virtual size of the viewfinder display is not directly related to the format size, but is based on the magnification relative to 50mm FOV (arbitrary standard)*. As such a FF viewfinder with 100% coverage at 1x magnification will have a diagonal 1.5x that of an APS-C viewfinder having 100% coverage at 1x magnification. The two will appear the same size if the FF viewfinder has 0.67 magnification or if the APS-C had 1.5x.

A real world example:

K-5 viewfinder is 100% coverage with 0.92x magnification
K-3 viewfinder is 100% coverage with 0.97x magnification
K-1 viewfinder is 100% coverage with 0.7x magnification

The K-1 viewfinder will appear a little larger than that of the K-3 and a notch more than the K-5. This is decent, but a notch off the Super Program (92% at 0.82x). Your diagram shows this nicely. FWIW, the ME Super is 92% at 0.95x and would appear significantly larger than the K-1.

Added: A bit of trivia...a 1x viewfinder may be used with both eyes open since the magnification is the same as unaided eye. With rangefinder cameras having such (rare), this is a distinct advantage in that it allows the photographer use of their peripheral vision.


Steve

* Why the same is applied to both FF and APS-C is beyond me. Regardless, the key is to think in terms of degrees of arc for the diagonal.
Yes, that is my understanding, too.

Frankly, I am disappointed in the angular size of viewfinder image in the K-1, compared to that of my ME Super. The latter is very nearly 25% larger.

I can only attribute this to the K-1 having been designed to display more "outside the image" data, as suggested in this image on the Ricoh website.

I will be pleased to discover that my fears are unfounded.

Attached Images
 

Last edited by Pentaxis; 03-09-2016 at 04:19 PM. Reason: Try to add image
03-09-2016, 04:55 PM   #5
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The K-1's viewfinder may not be the biggest, but it is still big if you compare to APSC camera's viewfinders.

For view finder comparison the crop factor needs to be counted in as well, so K-5's viewfinder would have full frame equivalent of 0.613x magnification and K-3 would have 0.647x magnification. The K-1's viewfinder has 0.7x magnification, though fairly standard amount today's full frame cameras, there is still quite some difference.

I used to have Canon 5D3 and Sony A900 both full frame cameras with 100% view coverage and used them side by side sometimes and I noticed quite some difference in viewfinder size. The Canon 5D3's viewfinder has 0.71x magnification and the Sony A900's viewfinder has 0.74x magnification, that seems to be small on paper but when you look through them against each other you see a big difference. BTW the difference between these 2 cameras's viewfinders are smaller then the difference between K-3's viewfinder comparing to K-1's.

I think there would definitely be a big difference if you compare them side by side. I also did compare 5D3's viewfinder against 1DX's viewfinder which has the biggest OVF on modern DSLRs at 0.76x magnification, the difference is huge! And again that's 0.05x increase in the magnification factor difference and about the same if you compare K-3's viewfinder against the K-1's. Sure I too hoped that K-1 has at least 0.72x or bigger as well, but even at 0.7x it is not small especially comparing to APSC cameras's viewfinders, just we expected more.
03-09-2016, 05:08 PM   #6
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QuoteOriginally posted by Pentaxis Quote
Frankly, I am disappointed in the angular size of viewfinder image in the K-1, compared to that of my ME Super. The latter is very nearly 25% larger.
Standards have changed since the early 1980s. The K-1 viewfinder is right in there with the rest of the current FF pack...sadly


Steve
03-09-2016, 05:16 PM   #7
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Hmm, that doesn't feel right. Putting the K-3 to one eye and the K-1 to the other, the viewfinders compare roughly like this (K-3 in red):
Attached Images
 

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03-09-2016, 05:58 PM   #8
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QuoteOriginally posted by ColiNiloK Quote
And again that's 0.05x increase in the magnification factor difference and about the same if you compare K-3's viewfinder against the K-1's.
To put everything in actual (degrees of arc) rather than relative units...

Diagonal FOV 50mm at infinity corrected by magnification and format

K-3 (APS-C) = 32.2 * 0.95 = 30.6
K-1 (24x36) = 46.8 * 0.7 = 32.8
5DM3 (24x36) = 46.8 * 0.71 = 33.2
A900 (24x36) = 46.8 * 0.74 = 34.6

Difference (A900 - K-3) = 4.0 (+12%)
Difference (K-1 - K-3) = 2.2 (+ 7%)
Difference (A900 - K-1) = 1.8 (+5%)
Difference (A900 - 5DM3) = 1.4 (+4%)
Difference (5DM3 - K-1) = 0.4 (+1%)



Note: I may have misunderstood how to do these calculations. I will update if I discover otherwise.

Steve


Last edited by stevebrot; 03-09-2016 at 09:27 PM.
03-09-2016, 06:15 PM   #9
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QuoteOriginally posted by Adam Quote
Hmm, that doesn't feel right. Putting the K-3 to one eye and the K-1 to the other, the viewfinders compare roughly like this (K-3 in red):
Agreed, which is why I calculated it out.

QuoteOriginally posted by stevebrot Quote
Difference (K-1 - K-3) = 2.2 (+ 7%)
Not as much as your graphic, but still a noticeable difference.


Steve

(...hmmm...Adam has a K-1 in hand!...)
03-09-2016, 07:03 PM   #10
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QuoteOriginally posted by stevebrot Quote
(...hmmm...Adam has a K-1 in hand!...)
If the diagonal is 7 longer (did I understand that correctly?) then the extra area covered is fairly significant (as depicted by Adam's diagram).

DO I understand?
03-09-2016, 09:09 PM   #11
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QuoteOriginally posted by monochrome Quote
If the diagonal is 7 longer (did I understand that correctly?) then the extra area covered is fairly significant (as depicted by Adam's diagram).

DO I understand?
The diagonal in the K-1 viewfinder describes 7 percent greater degrees of arc* than the K-3. I would have to sight with my protractor, but I think that Adam's diagram shows a larger discrepancy than that. 2.2 degrees of arc is not very much at a virtual distance of ~20". As for area, both viewfinders are 100%.


Steve

* Unfortunately viewfinder magnification is defined by FOV and the unit of FOV is degrees of arc.

Last edited by stevebrot; 03-09-2016 at 09:32 PM.
03-09-2016, 09:26 PM   #12
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QuoteOriginally posted by stevebrot Quote
Steve

(...hmmm...Adam has a K-1 in hand!...)
03-09-2016, 09:35 PM   #13
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Magnification and brightness, for a given lens aperture, are a trade-off against each other. If the K-1 viewfinder image is 7% larger (107% linear, 114.5% area) than that of the K-3, but is admitting 225% more light (1.5 squared) that means, all things being equal, that the K-1 viewfinder should be 1.97 times as bright as the K-3's. Even allowing for some transmission loss in the LCD overlay, that's got to be a significant advantage in terms of visibility.
03-09-2016, 10:04 PM   #14
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And now to put things in perspective a 2009 quote from Michael Reichmann:

QuoteQuote:
— Don’t accept less than .8X magnification unless the coverage is higher than 95%. Never accept less than .7X in any case — and accept less than .75X only if you’re getting 100% coverage in return.
https://luminous-landscape.com/understanding-viewfinders/

Read the article...it gets worse...

Steve
03-10-2016, 12:09 AM   #15
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QuoteOriginally posted by stevebrot Quote
To put everything in actual (degrees of arc) rather than relative units...

Diagonal FOV 50mm at infinity corrected by magnification and format

K-3 (APS-C) = 32.2 * 0.95 = 30.6
K-1 (24x36) = 46.8 * 0.7 = 32.8
5DM3 (24x36) = 46.8 * 0.71 = 33.2
A900 (24x36) = 46.8 * 0.74 = 34.6

Difference (A900 - K-3) = 4.0 (+12%)
Difference (K-1 - K-3) = 2.2 (+ 7%)
Difference (A900 - K-1) = 1.8 (+5%)
Difference (A900 - 5DM3) = 1.4 (+4%)
Difference (5DM3 - K-1) = 0.4 (+1%)


Thanks Steve, this makes more sense and gives a better perspective how the viewfinder sizes differs.

And if we were to continue going up in viewfinder size for full frame camera that's currently in production:

Canon 1DX/1DX II (0.76x Magnification OVF) 24x36= 46.8 * 0.76 = 35.6
Sony A7R II/A7S II (0.78x Magnification EVF) 24x36= 46.8 * 0.78 = 36.5
Leica SL (0.8x Magnification EVF) 24x36= 46.8 * 0.8 = 37.4

Difference (1DX/1DX II - K-3) = 5.0 (+16%)
Difference (1DX/1DX II - K-1) = 2.8 (+ 8.5%)
Difference (A7R II/A7S II - K-3) = 5.9 (+19%)
Difference (A7R II/ A7S II - K1) = 3.7 (+11%)
Difference ( SL - K-3) = 6.8 (+22%)
Difference ( SL - K-1) = 4.6 (+14%)

Honestly though from personal experience trying a 0.7x viewfinder (Nikon D800) vs 0.71x viewfinder(Canon 5D3) I can't notice any difference, but both comparing to the K-5II I use to have there is a massive difference. I only noticed difference comparing the viewfinder of 1DX with 5D3 and A900 with 5D3.

The K-1's viewfinder is the same size as D800's and honestly it is pretty big already, just there are cameras out there there with bigger viewfinders... and those cameras with bigger view finders cost lot more than the K-1( A900 aside, that is an old camera. Especially the Leica SL, you can buy a whole set of Pentax gear with that price), the biggest viewfinder for current production cameras are EVFs, some people like them and some don't them(I like them both personally ) so that's another thing.

And lastly a simple viewfinder magnifier should make the K-1's viewfinder much bigger.
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