If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Katz eye focusing screen.
In article , Michael Benveniste
writes "Matt Clara" wrote: My Nikon split prism for my F3HP blacks out on one side when I try to do macro, particularly with the bellows, so does my Mamiya RB67's. You can hold your eye back a little bit, and regain use of the split screen, but then your head isn't braced, and your a little farther from the "split" to see it and line up the two halves. That's likely because of the "bellows effect." At 1:1, an f/2.8 lens is effectively an f/5.6 lens, and most split image focus aids are only marginally usable at f/5.6 and unusable by f/8. The Katz eye prism claims to be usable down to f/11, but I've held off on buying/installing one since Nikon USA considers it a warranty-voiding modification. I would be more worried about the general problems an f/11 split image prism introduces rather than the advantage it provides in limited unique situations. An f/11 prism has no more than HALF the focus precision of an f/5.6 prism, and should ONLY be used when required (ie. when the f/5.6 prism does black out). If you want to understand why f/11 is less appropriate for faster lenses, read this description of HOW a split image viewfinder works. http://doug.kerr.home.att.net/pumpkin/Split_Prism.pdf The split image prism system is basically a rangefinder and at f/11 the baseline of the rangefinder is half that of f/5.6, with consequential effects on focus accuracy. In fact, in the not so old days, some manufacturers offered both slow and fast split image screens for precisely this reason. Holding up to f/11 may be a benefit when using such slow optics, but it certainly is NOT an "improvement" in general terms. If you plan to shoot fairly wide then you would be much better to use a screen that only operates to f/5.6 or even faster. -- Kennedy Yes, Socrates himself is particularly missed; A lovely little thinker, but a bugger when he's ****ed. Python Philosophers (replace 'nospam' with 'kennedym' when replying) |
#22
|
|||
|
|||
Katz eye focusing screen.
Paul Furman wrote in
: Probably 10 years since I used my old Canon AE1. I never really used the microprism collar on it through all those years either, I just used the split prism. I didn't get split prism focusing in an SLR until maybe my *third* one (fourth serious camera, there was a Leica M3 in there too). My first few were microprism only. And I converted my FM2 to a matte screen, no focusing aid at all. -- David Dyer-Bennet, ; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info |
#23
|
|||
|
|||
Katz eye focusing screen.
Paul Furman wrote in
: I got my Katz eye focusing screen in the mail yesterday and installed it today. I read their instructions for installing on a D200 (which they asked me *not* to post, incidentally...), and got scared off of self- installing. Which has kept me from getting one so far. It sounded like there were little shims that set the position of the screen, which if lost or misinstalled would cause manual focusing to be inaccurate due to screen mis-positioning. How did your actual installation go? Did it look like there were opportunities for that level of disaster? -- David Dyer-Bennet, ; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info |
#24
|
|||
|
|||
Katz eye focusing screen.
"Floyd L. Davidson" wrote:
The Katz eye prism claims to be usable down to f/11, but I've held off on buying/installing one since Nikon USA considers it a warranty-voiding modification. Really? That would be a bit silly of Nikon... and I find it pretty hard to believe. It *is* a customer replaceable component, no different than the carrying strap, for example. But I still don't see that as a problem anyway. If you warranty need work done, just put the original screen back in before handing it to Nikon. Really. I asked Nikon USA this specific question in March of 2006. The incident number was 060306-000163. As with all their replies, the email includes a prohibition on quoting it here, but my statement is consistent with their response. Unlike screens for other Nikon cameras, they do not consider a D200 screen a customer replaceable component. While _you_ might be able to put back in the original screen, I'm not so sure about my own abilities to do so without leaving some evidence. When I get one of these screens, I will have it installed by Katz-Eye or a local technician. It's possible that Nikon USA's stand has changed since then, so you may wish to ask them yourself. -- Michael Benveniste -- Spam and UCE professionally evaluated for $250. Use this email address only to submit mail for evaluation. |
#25
|
|||
|
|||
Katz eye focusing screen.
"Paul Furman" wrote in message ... David Ruether wrote: Paul Furman wrote I got my Katz eye focusing screen in the mail yesterday and installed it today. Installation instructions (slow loading PDF): http://www.katzeyeoptics.com/files/D200.PDF The split prism center aid does indeed help with manual focusing, in particular I had a heck of a time without it focusing the old 28mm f/2 at medium distances and even where I thought it was easy like closeups, the focusing aid gives me a little better confirmation. Funny - back in the "good old days" with really sharp Nikon viewfinders (before the N7007 and the N90, and before the center of my focus eye went soft), the first thing I did when I got a new body (which came with that %$#& split-image rangefinder and useless microprism, that just spoiled the view and didn't help at all with focusing [the center of the split needs to be on what? perpendicular edge how's that for handy? for accuracy, assuming 1/2 doesn't go dark - and I never could get Nikon's microprism to look different with the lens in or out of focus] - and it all just slowed me down) was to yank it out and replace it with the matte plus Fresnel screen Is that maybe what comes in the D200? The OOF does have a granular look to it. Still, it's cropped frame and not 100% either, even if it is a heck of a lot better than my D70 viewfinder was. Yes, the D80 and similar come with the basic matte plus outer area Fresnel (for edge brightening) screen. The "grind" in the matte screen gives the eye something to "stop" on for focus. Otherwise, as with clear screens, you would see no point of correct focus at all - though you could still use paralax focusing (tedious, and you need a reference mark in the finder). When you stop a lens down with the DOF preview, you see more clearly on the darker screen its texture. BTW, the smoother and brighter the screen is (achieved by reducing the level of texture), the harder it is to focus with the screen - so a compromise must be found. The same is true for the Fresnel at the edges - one optimized for some lenses will likely not work as well for others, and since the Fresnel offers a second (and different) layer in the optical path for the eye to "catch", it can reduce focus accuracy. Darn! ;-) that was so sharp that I could beat any AF system for accuracy and focus speed (until the F100/F5 came along, as well as my eye problem...). Fortunately, Nikon has again returned to making sharp matte screens (with diopter adjustment, too!), making an N80 almost as easy to focus as the F3/F2/F or the FE/FM/FA/8008. These matte screens give a better idea of what the texture and "feel" of OOF areas will I look like, also. I think I will not be paying extra for a screen type I have many of on my shelves since I didn't like them much when they came with the cameras...;-) There are trade-offs but like I said, lenses like the 28mm f/2 & fast 50mm are really hard to focus at distances more than a few feet away and it does help with that. -- Paul Furman Photography Are these lenses sharp wide open? Also, some lenses (or lens speeds) just do not mate well with the optics of some viewfinders. My guess is that your camera's stock VF is not designed to match speed lenses, since most DX lenses are f2.8 or even slower... -- David Ruether http://www.donferrario.com/ruether |
#26
|
|||
|
|||
Katz eye focusing screen.
Kennedy McEwen wrote:
In article , Michael Benveniste writes "Matt Clara" wrote: My Nikon split prism for my F3HP blacks out on one side when I try to do macro, particularly with the bellows, so does my Mamiya RB67's. You can hold your eye back a little bit, and regain use of the split screen, but then your head isn't braced, and your a little farther from the "split" to see it and line up the two halves. That's likely because of the "bellows effect." At 1:1, an f/2.8 lens is effectively an f/5.6 lens, and most split image focus aids are only marginally usable at f/5.6 and unusable by f/8. The Katz eye prism claims to be usable down to f/11, but I've held off on buying/installing one since Nikon USA considers it a warranty-voiding modification. I would be more worried about the general problems an f/11 split image prism introduces rather than the advantage it provides in limited unique situations. An f/11 prism has no more than HALF the focus precision of an f/5.6 prism, and should ONLY be used when required (ie. when the f/5.6 prism does black out). If you want to understand why f/11 is less appropriate for faster lenses, read this description of HOW a split image viewfinder works. http://doug.kerr.home.att.net/pumpkin/Split_Prism.pdf Page 11: "There are special modifications to the prisms (not involving a change in angle) that can mitigate this “blackout” effect down to smaller apertures than usual while still maintaining a desirable large baseline distance (in the interest of retaining greater “sensitivity” when a large aperture lens is in place). These modifications are used in some split prism focusing screens available today. The principle involved is proprietary, and is beyond the scope of this article." The split image prism system is basically a rangefinder and at f/11 the baseline of the rangefinder is half that of f/5.6, with consequential effects on focus accuracy. In fact, in the not so old days, some manufacturers offered both slow and fast split image screens for precisely this reason. Holding up to f/11 may be a benefit when using such slow optics, but it certainly is NOT an "improvement" in general terms. If you plan to shoot fairly wide then you would be much better to use a screen that only operates to f/5.6 or even faster. -- Paul Furman Photography http://edgehill.net Bay Natives Nursery http://www.baynatives.com |
#27
|
|||
|
|||
Katz eye focusing screen.
David Ruether wrote:
"Paul Furman" wrote in message ... David Ruether wrote: Paul Furman wrote I got my Katz eye focusing screen in the mail yesterday and installed it today. Installation instructions (slow loading PDF): http://www.katzeyeoptics.com/files/D200.PDF The split prism center aid does indeed help with manual focusing, in particular I had a heck of a time without it focusing the old 28mm f/2 at medium distances and even where I thought it was easy like closeups, the focusing aid gives me a little better confirmation. Funny - back in the "good old days" with really sharp Nikon viewfinders (before the N7007 and the N90, and before the center of my focus eye went soft), the first thing I did when I got a new body (which came with that %$#& split-image rangefinder and useless microprism, that just spoiled the view and didn't help at all with focusing [the center of the split needs to be on what? perpendicular edge how's that for handy? for accuracy, assuming 1/2 doesn't go dark - and I never could get Nikon's microprism to look different with the lens in or out of focus] - and it all just slowed me down) was to yank it out and replace it with the matte plus Fresnel screen Is that maybe what comes in the D200? The OOF does have a granular look to it. Still, it's cropped frame and not 100% either, even if it is a heck of a lot better than my D70 viewfinder was. Yes, the D80 and similar come with the basic matte plus outer area Fresnel (for edge brightening) screen. The "grind" in the matte screen gives the eye something to "stop" on for focus. Otherwise, as with clear screens, you would see no point of correct focus at all - though you could still use paralax focusing (tedious, and you need a reference mark in the finder). When you stop a lens down with the DOF preview, you see more clearly on the darker screen its texture. BTW, the smoother and brighter the screen is (achieved by reducing the level of texture), the harder it is to focus with the screen - so a compromise must be found. The same is true for the Fresnel at the edges - one optimized for some lenses will likely not work as well for others, and since the Fresnel offers a second (and different) layer in the optical path for the eye to "catch", it can reduce focus accuracy. Darn! ;-) that was so sharp that I could beat any AF system for accuracy and focus speed (until the F100/F5 came along, as well as my eye problem...). Fortunately, Nikon has again returned to making sharp matte screens (with diopter adjustment, too!), making an N80 almost as easy to focus as the F3/F2/F or the FE/FM/FA/8008. These matte screens give a better idea of what the texture and "feel" of OOF areas will I look like, also. I think I will not be paying extra for a screen type I have many of on my shelves since I didn't like them much when they came with the cameras...;-) There are trade-offs but like I said, lenses like the 28mm f/2 & fast 50mm are really hard to focus at distances more than a few feet away and it does help with that. -- Paul Furman Photography Are these lenses sharp wide open? Sharp enough for a tiny viewfinder perspective. Also, some lenses (or lens speeds) just do not mate well with the optics of some viewfinders. My guess is that your camera's stock VF is not designed to match speed lenses, since most DX lenses are f2.8 or even slower... Unfortunately you cannot see the improvement of lenses faster than f/2 or f/2.8 in the viewfinder. This has been discussed here and no authorative explanation discovered. My best guess is some obstruction in light path due to smaller mirror perhaps in a less than 100% viewfinder. The diameter of OOF circles above f/2 or so does not increase in the viewfinder compared to what pops up on the LCD after shooting the actual image. -- Paul Furman Photography http://edgehill.net Bay Natives Nursery http://www.baynatives.com |
#28
|
|||
|
|||
Katz eye focusing screen.
David Dyer-Bennet wrote:
Paul Furman wrote in I got my Katz eye focusing screen in the mail yesterday and installed it today. I read their instructions for installing on a D200 (which they asked me *not* to post, incidentally...), and got scared off of self- installing. They provide the public web link in the package. Which has kept me from getting one so far. It sounded like there were little shims that set the position of the screen, which if lost or misinstalled would cause manual focusing to be inaccurate due to screen mis-positioning. How did your actual installation go? Did it look like there were opportunities for that level of disaster? I read that too but nothing fell out. There isn't any diagram or photo showing what those shims look like. -- Paul Furman Photography http://edgehill.net Bay Natives Nursery http://www.baynatives.com |
#29
|
|||
|
|||
Katz eye focusing screen.
"Michael Benveniste" wrote:
"Floyd L. Davidson" wrote: The Katz eye prism claims to be usable down to f/11, but I've held off on buying/installing one since Nikon USA considers it a warranty-voiding modification. Really? That would be a bit silly of Nikon... and I find it pretty hard to believe. It *is* a customer replaceable component, no different than the carrying strap, for example. But I still don't see that as a problem anyway. If you warranty need work done, just put the original screen back in before handing it to Nikon. Really. I asked Nikon USA this specific question in March of 2006. The incident number was 060306-000163. As with all their replies, the email includes a prohibition on quoting it here, but my statement is consistent with their response. Unlike screens for other Nikon cameras, they do not consider a D200 screen a customer replaceable component. Okay. If the D200 is different, it might well be exactly as you are describing. I was assuming, and might be totally wrong, that it was similar to the D2 series. While _you_ might be able to put back in the original screen, I'm not so sure about my own abilities to do so without leaving some evidence. When I get one of these screens, I will have it installed by Katz-Eye or a local technician. It's possible that Nikon USA's stand has changed since then, so you may wish to ask them yourself. -- Michael Benveniste -- Spam and UCE professionally evaluated for $250. Use this email address only to submit mail for evaluation. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#30
|
|||
|
|||
Katz eye focusing screen.
Kennedy McEwen wrote:
I would be more worried about the general problems an f/11 split image prism introduces rather than the advantage it provides in limited unique situations. An f/11 prism has no more than HALF the focus precision of an f/5.6 prism, and should ONLY be used when required (ie. when the f/5.6 prism does black out). If you want to understand why f/11 is less appropriate for faster lenses, read this description of HOW a split image viewfinder works. http://doug.kerr.home.att.net/pumpkin/Split_Prism.pdf This (quite interesting) source does _not_ say that an f/11 prism must have a reduced baseline, to the contrary! | There are special modifications to the prisms (not involving a change | in angle) that can mitigate this "blackout" effect down to smaller | apertures than usual while still maintaining a desirable large | baseline distance (in the interest of retaining greater "sensitivity" | when a large aperture lens is in place). These modifications are used | in some split prism focusing screens available today. The principle | involved is proprietary, and is beyond the scope of this article. (Page 11, last paragraph, of above URL) -Wolfgang |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Katz Eye screen for Nikon D50 works great on D40 | Alexander Arnakis | Digital SLR Cameras | 6 | March 20th 07 10:38 PM |
Katz Eye focusing screen | Jeremy Nixon | Digital SLR Cameras | 40 | June 23rd 06 11:11 PM |
Haoda vs Katz focussing screen for Canon 300D | Siddhartha Jain | Digital SLR Cameras | 0 | September 13th 05 04:01 PM |
EOS 3 Focusing Screen | Lee Hiers, AA4GA | 35mm Photo Equipment | 6 | October 20th 04 06:49 AM |
FA: Canon F-1 Focusing screen L (B) | zennyone | 35mm Equipment for Sale | 0 | April 3rd 04 09:13 PM |