A question on focussing

[Valerio Trigari]

Hello there,

this is a question for those among you who are bespectacled like me: do you find it difficult to focus correctly on ground glass sometimes? There have been a few occasions where the combination of spectacles and focussing loupe made it very hard to focus for me, to the point I couldn't actually focus...

Did anyone else experience this? Any way to avoid this issue you may know?

Cheers,

Valerio

[dennis]

I use reading specs to look thro the loupe. Dennis

[Alex Timmermans]

Valerio,

I wear glasses and have no problems.
BUT, it al depends what kind of loupe you are using.
A few months ago i bought an old Hermagis loupe. It turned out to be MUCH better than my normal loupe.
Have a look at my weblog and search for loupe

It was more vibrant and much easier to focus with.
So, if you havent, buy yourself a very good loupe.

Alex

[Neil Barnes]

I'm farsighted and need glasses for anything nearer than a couple of feet; even with the glasses I find I can't see nearer than a foot or so.

But at least that means positive lenses in loupes and such are the right direction for me. I use an 'old folks reading aid' - credit card sized thing with an approximate *3 over most of it and about a *8 segment in one corner.

Seems to work for me - though I'm not 100% certain that the glass and the film are in the same position, which makes it all a bit moot...

Neil

[Susie Frith]

Hi Valerio,

Like Neil, anything closer than a couple of feet and I need glasses.

Several years ago when I had my eyes tested, I also had a perscription made up for a pair of glasses that will focus at about 7 inches. There is very little depth of focus at that range, and I have to keep them perched on the end of my nose except when focusing, but it does mean that I can see the ground glass okay, and also set the shutter. They also mean that I have both hands free to operate the camera.

The other way of focusing your Linhof is to use the bag-cum-loupe that attaches onto the camera back. They are expensive (welcome to Linhof!) but work very well, and give you two focal lengths of loupe. I have them in both 5x4 and 6x7 sizes. Your welcome to try one, but they are rather tatty! The only problem I have using them, is that I still need glasses to see the shutter controls.

Susie

[Trail Images]

About two years ago I noticed I was struggling to focus on the ground-glass more so then ever before. I'd bought a variety of loupes over time trying to resolve the issue without much luck. I have been wearing glasses for about 20 years now for an astigmatism. I'd also been having issues working long hours on the PC both at work and at home. My eye doctor made up a set of prescription computer glasses for me that worked great for PC needs and most recently resolved the long two year battle with trying to focus on the ground-glass using my normal glasses. Again, these newer ones are prescription so it corrects the issue with astigmatism but also short range vision is much improved as well. It is a pain carrying two sets of glasses into the field, but the end results are more then worth the necessary swopping back and forth. Additionally, I find most of my loupes seem to work better now. Although, I will say I find my older Rodenstock still my favorite.

[Neil Barnes]

Something similar to this is what I use. It's a bit of a pain if I have the screen light-screens up, but if I remove those and use a cover, it's fine.

<edit> for got to put the link in! http://www.ebay.co.uk/itm/3X6X-Magnifyi ... 7587556364

Neil

[Georges Giralt]

Hello Valerio,
since I was a kid, everything has been fuzzy. Of course, with a pair of glasses on my nose everything came out clear; since I'm 50, the situation start to reverse a bit. To do delicate things or to read, I quit my spectacles !
Of course I now have varifocal glasses on my nose.
All this to say that I know perfectly what kind of problem you face. I've found that stepping away a little from the ground glass and looking at it from there makes the focusing easier. I seldom use the loupe these days, and nobody complains ! So maybe you should try my method. Last but not least, try to move your eye during focusing with the loupe. Our old eyes are prone to defocus when forced to look at the very same image for a long time. They become bored, it seems...

[Valerio Trigari]

Hello and thank to everyone for replying to me about this issue. At least I'm not the only one who had this problem! I noticed that sometimes I need to stop trying focussing, step away and then try again. I fear that sometime the relative position of the loupe on my glasses lens could also affect focussing, but that's just a wild guess. Mine in a Silvestri loupe, so I think it's of good quality.

[Paul Jenkin]

Apologies for hijacking this thread but I also have a question on focusing.

What is the best point in the sequence of setting up the camera to focus? Sorry if this sounds a weird question to ask but this will be the first time I've set the camera up and I don't want to set the thing up get it in focus and then need to make movements that knock the focus out of whack unless that's the order in which I need to work.

Does anyone have a flowchart or some ordered list of things to attend to when setting up a Wista 45 Field camera, please?

[Joanna Carter]

Hi Paul.

Focussing and tilt are inter-related.

First of all, decide whether you need to apply tilt or not.

if you need to apply tilt, it will affect the focus, as you are changing from having a plane of sharp focus that is parallel to the film, to a plane of focus that will be at an angle, going away from the camera to infinity.

If I remember rightly, the Wista 45 has base tilt (correct me if I am wrong); in which case, you could be better of starting by focussing on something in the foreground and then tilting to get the distance in focus. Cameras with axis tilt tend to work easier the other way around.

But beware; the biggest fault for people who have never used tilt is to tend to use too much and to try and put it all on at once. Once you have your distance in focus, apply a little tilt, so that the foreground only starts to come into focus. Then refocus so that the distance comes back into focus, then apply slightly more tilt until the foregrouond gets more into focus. This is best done as an iterative process, which can take as few as three or four iterations, sometimes more.

Most beginners hear about needing 6° of tilt for a 90mm lens, for a plane of focus that follows the ground going away from you. But that is based on simple principles of getting everything on the ground in focus with a 90mm lens. If you want to get everything on the ground in focus and the whole of a tall building in the near distance in focus, then you need to set the foreground in focus and a point about halfway up the building. That way, when you stop down, the depth of field will increase to cover the ground going away from you, rather than "wasting" half the depth of field below the ground.

I have shown this picture before but it bears repeating:



To get the prow of the boat, which is quite high in the foreground, the river bed and water, which is twenty or so feet below the ground, and the distance all in focus, I needed a very, very small tilt, hardly any movement at all.

[Emmanuel Bigler]

rather than "wasting" half the depth of field below the ground.

.. hence, instead of Scheimpflug's rule, real Scheimpflug aficionaods, in real life, prefer ...
Ze Semi-Scheimpflug

[Joanna Carter]

Ze Semi-Scheimpflug

Exacte ! So now we have a new language developing; I talk about "micro-tilt" (comme le poil de chien) and now you discover "semi-Scheimpflug". What next?

[Steve France]

Hi everyone,
Im new to large format to and have a question on focusing, again sorry for throwing this in here.

Im only using a 150mm 5.6 lens at present, and Ive been try to 'push' things a bit in terms of getting close to subjects AND having front to back sharpness using tilt. Ive had a few issues where the image i have photographed , for example field of long grass, tree 2/3rd into the frame and taller trees behind as bg subject.. where the trunk of the tree 2/3's in is soft.. everything else is sharp. I'm not sure how this has happened. I placed my plane from about 1/3rd up the fg grass to the top of the trunk/ base of leaves in the tree 2/3rd in (that was about 30ft away) and I stopped down to f32. I pointed the camera down, moved the rear standard back to vertical, and then started my focusing/checking applying tilt in micro movements until my plane was as I wanted it. So im unsure as to why the trunk is soft?

Being a novice I may still not be using the correct plane.. I would like to not stop down so much, but i think this is all down to using a standard lens rather than one with a wider angle of view?

I like my more initmate landscapes, and I realise movements cant necessarily be applied in every situation (forests right now are what Im doing and not getting great results with just stopping down as you would with a ridged back camera).. but to get closer and have a wider view, I know a wider lens is needed.. but i find a 150 wide enough lol

If I changed to a 210 or 240... how if anything would like change what I'm doing, other than getting closer?

Joanna.. your image is a good example...as thus far.. ive not managed to get eveything in sharp focus.. if that were my pic, the boat may of been ok.. but the nearest sand by the boat would be out of focus (or maybe even the very top of the boat)

Also do I need to move the front standard to vertical everytime I do this sort of composition and set up of camera? Does not moving it to veritcal have any effect on focus, plane of focus, dof etc..?

many thanks!!!
Steve

[Valerio Trigari]

Hi Steve,

I know what it feels like, I've been into the LF world for a few months only and I still have some problems with the use of tilts and swings, though now I get things right more often. I found this gizmo very useful viewtopic.php?f=3&t=2911

I had a similar problem yesterday, while shooting in the West Brompton Cemetery. I thought I did everything right, but when I scanned the negative, the most important part of the picture (the tombstobe in the foreground) was out of focus... D'oh!

I'll upload the picture this evening, so that I can ask help to experts. Maybe you could do the same, so that we (or better to say they, the experts) can see what's wrong with your focussing.

Cheers and welcome to the forum,

Val