[Guest]

[quote name='larsrc' date='20 July 2010 - 11:15 AM' timestamp='1279617327' post='1150']

I believe my own eyes over those calculations. If the viewfinder showed f/5.6 regardless of aperture, you wouldn't see any DOF effect of using the DOF preview button. I see a very clear effect. I'm guessing those calculations talked about using an f/2.8 lens.



-Lars

[/quote]



I think I see what you're talking about. [url="http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-dslr-viewfinder/"]A comment here[/url] talks about how the viewfinder as such has an aperture (sorta), which they claim is about f/4 for APS-C. Indeed, if I take my f/1.8 and do DOF preview to f/2.8, I see virtually no change, but on an f/5.6 lens DOF preview to f/8 gives about a stop of darkening and shows a difference in DOF. It's a gradual effect, no surprise. Stopping the f/1.8 down to f/4, I can barely see any change in DOF (letters appear slightly sharper), but the viewfinder does dim somewhat. Stopping down to f/5.6 clearly shows a difference in DOF. This matches well with what that thread said.



So a more precise description is that the viewfinder doesn't show apertures larger than about f/4, but the effect of smaller apertures can be seen. I might have misconstrued what you said, I understood it as if the viewfinder always showed f/5.6, even at smaller apertures.



Yet another advantage to FF and Live View.



-Lars

[wim]

[quote name='larsrc' date='20 July 2010 - 11:15 AM' timestamp='1279617327' post='1150']

I believe my own eyes over those calculations. If the viewfinder showed f/5.6 regardless of aperture, you wouldn't see any DOF effect of using the DOF preview button. I see a very clear effect. I'm guessing those calculations talked about using an f/2.8 lens.



-Lars

[/quote]

Well, no ,that is not exactly what I am saying. What I am saying is that you get about F/5.6 to start with. If you stop down further, you will get a view with even more DoF.



So yes, you will always see an effect in the viewfinder when you use the preview button.



Kind regards, Wim

[wim]

[quote name='larsrc' date='20 July 2010 - 01:03 PM' timestamp='1279623798' post='1156']

I think I see what you're talking about. [url="http://www.dphotoexpert.com/2007/09/21/live-view-versus-the-cheating-dslr-viewfinder/"]A comment here[/url] talks about how the viewfinder as such has an aperture (sorta), which they claim is about f/4 for APS-C. Indeed, if I take my f/1.8 and do DOF preview to f/2.8, I see virtually no change, but on an f/5.6 lens DOF preview to f/8 gives about a stop of darkening and shows a difference in DOF. It's a gradual effect, no surprise. Stopping the f/1.8 down to f/4, I can barely see any change in DOF (letters appear slightly sharper), but the viewfinder does dim somewhat. Stopping down to f/5.6 clearly shows a difference in DOF. This matches well with what that thread said.



So a more precise description is that the viewfinder doesn't show apertures larger than about f/4, but the effect of smaller apertures can be seen. I might have misconstrued what you said, I understood it as if the viewfinder always showed f/5.6, even at smaller apertures.



Yet another advantage to FF and Live View.



-Lars

[/quote]

Yes, I didn't mean it is always F/5.6. It is slightly different. The DoF will increase with closing down the aperture and using the preview button,, just that you will see a noticeable effect until upwards of F/4 - F/5.6.



I actually did a test once, with macro, and a few lenses with extension tubes mounted, with different focusing screens, and MF, i.e., moving the camera to an area so that a specific part of the subject looked sharp in the VF. With the standard focusing sceen I was off by more than half of the shots, with de precision matte only by about 10 %. This I attribute to DoF perception (especially when checked against LiveView).



For ultimate precision, LiveView and 10X magnification is best, however <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. An Angle Finder at 2.5X magnification is second best <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.



Kind regards, Wim

[canoman]

Changing the focussing screen can be a bit dodgy for the clumsy fingers person. Not like the old Canon F1n camera where you had a choice with many screens. Just clip in or out.

[Rainer]

[quote name='geriatric' timestamp='1281334970' post='1590']

Changing the focussing screen can be a bit dodgy for the clumsy fingers person. Not like the old Canon F1n camera where you had a choice with many screens. Just clip in or out.

[/quote]



Well, but it is also not rocket science ...



I changed the screen of my 5D(1) recently, and found it is much

easier than it was on the 300D (which was not really intended to

have the screen changed). I just followed the instructions that came

with the new screen and did the change within 5 minutes.



Just my 2cts ... Rainer

[wim]

[quote name='geriatric' timestamp='1281334970' post='1590']

Changing the focussing screen can be a bit dodgy for the clumsy fingers person. Not like the old Canon F1n camera where you had a choice with many screens. Just clip in or out.

[/quote]





[quote name='Rainer' timestamp='1281338907' post='1591']

Well, but it is also not rocket science ...



I changed the screen of my 5D(1) recently, and found it is much

easier than it was on the 300D (which was not really intended to

have the screen changed). I just followed the instructions that came

with the new screen and did the change within 5 minutes.



Just my 2cts ... Rainer

[/quote]

Exactly. And even on the 40D/50D it is a doddle.



Do it twice, and it'll take you more time to open the focusing screen container than actually changing the focusing screen...



Kind regards, Wim

[adifrank]

Hi. Thanks for all the information. I think I will order the Eg-S focus screen, since I figure I'll mostly be using MF. Only two questions:



1. How exactly does this screen improve manual focusing? Is there a particular technique used for this? From the images of the screen I've seen on the internet it doesn't look like there is a horizontal split image or something similar - it looks just blank.



2. How does using the Eg-S with Canon 5D mark ii affect using auto-focus? As it seems there are no focus points marked on the screen - how does AF work?



Thanks.

[wim]

[quote name='adifrank' timestamp='1281365421' post='1610']

Hi. Thanks for all the information. I think I will order the Eg-S focus screen, since I figure I'll mostly be using MF. Only two questions:



1. How exactly does this screen improve manual focusing? Is there a particular technique used for this? From the images of the screen I've seen on the internet it doesn't look like there is a horizontal split image or something similar - it looks just blank.[/quote]

It works because it actually is what it says it is, a precision matte. In non-technical terms this means it is a very fine polished focusing screen, as compared to the rather coarsely polished standard focusing screen. Because it has such a fine structure, it represents DoF much, much more accurately than de standard focusing screen does, e.g., narrow DoF actually appears as narrow as it is, hence making MF much easier. The only disadvantage is that it is slightly less bright than a standard focusing screen, but to be very honest, not noticeably so.



This screen also allows you to MF anywhere on the screen, rather than only in the centre, like a screen with a split prismatic wedge in the centre, because it is the same precison matte all over. Furthermore, it doesn't become unusuable when stopping down or when the light levels get low: it just gets a little darker (ok, that's obviosu <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt=':lol:' />), unlike a wedge which just goes half black, or completely black. Since the 5D II has such a bright VF, I find this little loss of brightness isn't a problem anyway. By the time I can't focus with it anymore with MF, I find the AF system has already thrown in the towel for some time already. I am talking light levels here like 1/15s with an F/5.6 lens and 3200 iso.

2. How does using the Eg-S with Canon 5D mark ii affect using auto-focus? As it seems there are no focus points marked on the screen - how does AF work?



Thanks.

You don't see those on the standard focusing screen either. The lights are projected in, and the screen actually has some support built into it anyway, even if you don't see it. Some raised or lowered edges I'd think. This is why the focusing screens for the 1 Ds II, III and 1 D II and III are interchangeable: they have the same size screen and the AF points in the same position. The 1 D Mk IV has different ones and therefore requires different focusing screens. In short: you will see the red rectangular AF point highlights with this screen, just as before.



The only thing you shouldn't forget is to switch the support in Custom Functions IV to the correct screen, as metering is affected by the slightly darker Eg-S screen: the metering system is located in the prism housing, IOW, in the lightpath aftter the focusing screen, and hence gets a little less light too because of the slightly dimmer VF. The setting makes sure the metering systems takes this small loss into account. I reckon it is about 1/3 to 1/4 of a stop.



Kind regards, Wim

[adifrank]

Understood. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt=':lol:' />



Thanks Wim. I will order it tomorrow.

[Steinar1]

I have followed the thread of this discussion from the beginning. May I suggest that you also read a book on photography technique and take a course. Your questions show that you need them and the 5d MkII is an animal that you can only get something out of if you understand its capabilities. Otherwise you might as well have a good compact.I am not meaning to be unkind! <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />