Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-10-2016, 08:03 AM   #16
Pentaxian




Join Date: May 2011
Location: Santa Cruz, CA
Photos: Albums
Posts: 1,929
QuoteOriginally posted by ColiNiloK Quote
And lastly a simple viewfinder magnifier should make the K-1's viewfinder much bigger.
Unfortunately that comes at a significant loss of light.

As photographers, we're used to working with what we have. As the song goes, "If you can't be with the one you love, love the one you're with."


Last edited by LesDMess; 03-10-2016 at 08:10 AM.
03-10-2016, 08:42 AM   #17
Forum Member
Pentaxis's Avatar

Join Date: Jul 2012
Posts: 89
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%)



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

Steve
Yes. This is disappointing.

As I said in my original posting, my expectations are conditioned by use of the ME Super: this, as you agreed in your earlier earlier posting, has a beautiful finder. It calculates as being 25% bigger than the K-1. Gulp!

I have never used a digital SLR at all and am trying to understand why there is the apparent substantial reduction in finder field of view. One reason might be that the eye relief is greater on the K-1. The other might be, as I suggested ealier, that there is a need to display more symbology outside the imege field.
03-10-2016, 08:55 AM   #18
Lens Buying Addict
monochrome's Avatar

Join Date: Mar 2008
Location: Kirkwood (St. Louis) MO
Photos: Gallery | Albums
Posts: 19,462
QuoteOriginally posted by Pentaxis Quote
Yes. This is disappointing.

As I said in my original posting, my expectations are conditioned by use of the ME Super: this, as you agreed in your earlier earlier posting, has a beautiful finder. It calculates as being 25% bigger than the K-1. Gulp!

I have never used a digital SLR at all and am trying to understand why there is the apparent substantial reduction in finder field of view. One reason might be that the eye relief is greater on the K-1. The other might be, as I suggested ealier, that there is a need to display more symbology outside the imege field.
Given the uniquity of AF lenses, viewfinder acuity today is not as high a priority as it was in the 70's.
03-10-2016, 10:58 AM   #19
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,189
QuoteOriginally posted by monochrome Quote
Given the uniquity of AF lenses, viewfinder acuity today is not as high a priority as it was in the 70's.
...and there is the dirty little secret that the PDAF system steals a significant amount of light from the optical viewfinder path*. The resulting side-effects severely degrade the ability of the designer to offer decent viewfinder size, brightness, and focus sensitivity.


Steve

* It is not immediately obvious, but the main mirror is half-silvered.

03-10-2016, 12:59 PM   #20
Pentaxian
RobA_Oz's Avatar

Join Date: Nov 2008
Location: Tasmania, Australia
Photos: Gallery
Posts: 4,121
QuoteOriginally posted by LesDMess Quote
Unfortunately that comes at a significant loss of light.
There'll be some (small) transmission loss in a magnifier, but magnification lowers the brightness in proportion to the square of the magnification factor. Given that the viewfinder image in the K-1 will be nearly twice as bright as that in the K-3, a 1.3x magnifier will lower that by a factor of 1.69, so the resultant eyepiece image will be bigger and a little brighter than that of the naked K-3 eyepiece. It isn't all bad.
03-10-2016, 01:28 PM   #21
Site Supporter




Join Date: May 2009
Location: Seattle, WA
Posts: 828
Bummer the K-1's finder isn't going to be bigger. I shoot hybrid (film + digital) regularly and the difference in switching between my K-5 IIs and LX or K1000 is substantial: the big, beautiful viewfinders on the film cameras just blow the poor little K-5 out of the water. Was really hoping the K-1 would be more competitive with the old film finders.
03-10-2016, 02:56 PM   #22
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,189
QuoteOriginally posted by RobA_Oz Quote
Given that the viewfinder image in the K-1 will be nearly twice as bright as that in the K-3
That is the second time you have said that and I am puzzled. For a given relative aperture (f number) the luminance flux to the focus screen is the same regardless of the crop.* Edit: I had forgotten about the reduction in magnification effectively concentrating the light to that of the smaller apparent area. Many thanks to @Cannikin for reminding me of how things work.


Steve

* There are assumptions regarding attenuation due to incident angle at the margins. Some fall-off in the corners is unavoidable.

Last edited by stevebrot; 03-10-2016 at 06:43 PM.
03-10-2016, 02:59 PM   #23
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,189
QuoteOriginally posted by alan_smithee_photos Quote
Was really hoping the K-1 would be more competitive with the old film finders.
Pentax (along with most other makers) has not fielded a decent optical viewfinder in any of their 35mm AF bodies. Welcome to the unintended future.


Steve

03-10-2016, 05:47 PM   #24
Site Supporter




Join Date: Mar 2010
Location: SW Washington
Posts: 814
QuoteOriginally posted by stevebrot Quote
That is the second time you have said that and I am puzzled. For a given relative aperture (f number) the luminance flux to the focus screen is the same regardless of the crop.
Except the image in the viewfinder is not the focusing screen itself. You are looking at a projection from the pentaprism in which the light passing through the FF focusing screen, with over twice the area of APS-C, is concentrated into a visual area only slightly larger than a K-3's pentaprism projection.

It is the same principle as to why a focal reducer ("speed booster") creates a brighter image, and a teleconverter creates a darker image.
03-10-2016, 06:39 PM - 1 Like   #25
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,189
QuoteOriginally posted by Cannikin Quote
You are looking at a projection from the pentaprism in which the light passing through the FF focusing screen
OK, let me walk myself through this...The image is not an aerial image. It is projected on the surface of the screen in the same manner as the ground glass on my view camera and the focus screen is the same size as the sensor. It is that image that is used by the camera meter system. What I had forgotten is that reduction in magnification is accomplished by the optical system of the prism and viewfinder ocular. So, you and @RobA_Oz are correct and I am mistaken. There would be amplification of brightness on the order of what RobA_Oz suggested. I will edit my comment appropriately.

How Ricoh/Pentax uses that extra brightness might prove interesting.


Steve

Last edited by stevebrot; 03-10-2016 at 07:35 PM.
03-10-2016, 08:03 PM   #26
Forum Member




Join Date: Aug 2011
Location: Michigan
Posts: 85
QuoteOriginally posted by alan_smithee_photos Quote
Bummer the K-1's finder isn't going to be bigger. I shoot hybrid (film + digital) regularly and the difference in switching between my K-5 IIs and LX or K1000 is substantial: the big, beautiful viewfinders on the film cameras just blow the poor little K-5 out of the water. Was really hoping the K-1 would be more competitive with the old film finders.
This is exactly what I do as well (film + digital). The difference between the LX FA-1 and K-5 is pretty mind blowing. I am hoping the difference between the LX FA-1 and the K-1 is a little less shocking. Some other random observations (not spec based): To me the Super A is noticeably smaller than the LX but is still very usable. I think the Super A must be much brighter than the K-5 for example. I can't see any difference between the ME Super and the LX FA-1 even though the ME Super is somewhat smaller. I am hoping for a difference between the LX and the K-1 that is similar to the difference between LX and the Super A. Based on the calculations here and my own, it should be close-ish.

QuoteOriginally posted by stevebrot Quote
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.
I have done this with the LX FA-1 and a 50mm lens and it worked for me.
03-10-2016, 08:40 PM   #27
Pentaxian




Join Date: May 2011
Location: Santa Cruz, CA
Photos: Albums
Posts: 1,929
QuoteOriginally posted by RobA_Oz Quote
There'll be some (small) transmission loss in a magnifier, but magnification lowers the brightness in proportion to the square of the magnification factor. Given that the viewfinder image in the K-1 will be nearly twice as bright as that in the K-3, a 1.3x magnifier will lower that by a factor of 1.69, so the resultant eyepiece image will be bigger and a little brighter than that of the naked K-3 eyepiece. It isn't all bad.
I have a variety of magnifiers that are helpful but all will darken the viewfinder and of course not useful unless tripod mounted like live view.

Good or bad it doesn't matter now that the K-1 features are solidified. Hopefully it will be successful enough so we can possibly get these features added to the next one . . .
03-10-2016, 09:33 PM   #28
Pentaxian
RobA_Oz's Avatar

Join Date: Nov 2008
Location: Tasmania, Australia
Photos: Gallery
Posts: 4,121
QuoteOriginally posted by LesDMess Quote
I have a variety of magnifiers that are helpful but all will darken the viewfinder and of course not useful unless tripod mounted like live view.

Good or bad it doesn't matter now that the K-1 features are solidified. Hopefully it will be successful enough so we can possibly get these features added to the next one . . .
Yes they do, as I said, but if the resultant eyepiece image is both bigger and brighter (even with a magnifier of less than 1.5x), then we can all relax about this, because we're doing better than we have now (which isn't all that bad, really).

With my slowly declining eyesight, I need all the luminous flux I can get, especially with an OVF (and, yes, I do have an EVF camera, as well).
03-10-2016, 09:54 PM   #29
Pentaxian




Join Date: May 2011
Location: Santa Cruz, CA
Photos: Albums
Posts: 1,929
QuoteOriginally posted by RobA_Oz Quote
Yes they do, as I said, but if the resultant eyepiece image is both bigger and brighter (even with a magnifier of less than 1.5x), then we can all relax about this, because we're doing better than we have now (which isn't all that bad, really).

With my slowly declining eyesight, I need all the luminous flux I can get, especially with an OVF (and, yes, I do have an EVF camera, as well).
No doubt a reference is needed here but unfortunately my point of reference has no equal in the viewfinder department. I understand that the priority is reliance on autofocus so it is what it is.
03-12-2016, 10:40 AM - 1 Like   #30
Loyal Site Supporter




Join Date: Mar 2012
Location: Rochester, NY
Photos: Gallery
Posts: 1,813
I have to admit that I am put off by the .7x magnification of the viewfinder. When I got to this fact when reading the specs it really deflated me. I was hoping for a viewfinder more akin to my Ricoh XRM or Pentax Spotmatic II. I want a split image center surrounded by a micro prism circle for my old eyes, I prefer manual focus to auto focus. Most of the shots with my Tamron 70-210 F2.8 and Pentax 150-450 are made using manual focus.

After 45 years of using manual focus lenses I am pretty good at it. But I need a better viewfinder to help me accomplish this. Focus confirmation on my K5 is spotty at best. My k5-IIs is a bit better and the K3 even better, but I want the lens to focus where I want to it and not some computer algorithm. I'm really bummed out about this. Pentax let me down a bit with this camera. It has been a long wait and I had hoped for a true full frame camera in all respects. And yes I was prepared to pay for it. I will probably still get it, but not until after actually handling one.

I know I am sounding old and set in my ways, but not all the old ways are the wrong way.

On a happier note, the crocuses are in full bloom with it the promise of spring and for me personally, retirement.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
24x36mm, af, brightness, eyepiece, fan, full-frame, image, innovations, k-1, k5, lens, light, lx, pentax, portion, screen, sensor, size, steve, systems, view finder size, viewfinder, viewfinder image, viewfinders
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Size comparison - FA* 24mm cali92rs Pentax SLR Lens Discussion 13 11-13-2015 05:00 AM
right angle view finder Tony S Troubleshooting and Beginner Help 5 03-09-2015 11:22 AM
Cracked View Finder MrHowell Pentax K-3 3 02-01-2015 09:07 PM
Moire in view finder only and fuzzy look through view finder Indy78 Troubleshooting and Beginner Help 13 06-11-2014 11:36 AM
View finder vs Live View on K5 II Wingincamera Pentax K-5 5 12-08-2012 03:47 PM



All times are GMT -7. The time now is 10:42 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top