Grain Focuser

mbisc

mbisc

Silver Halide User
Local time
4:29 PM
Joined
Mar 3, 2006
Messages
666
Location
Phoenix, AZ
View My Gallery
Quick question -- a couple of years ago when I first set up my darkroom, I picked up a used Paterson Micro Focus Finder grain focuser on eBay.

I have no problems with it, but I was wondering if any of the other ones out there (including more expensive ones) are any better in getting me sharper prints, and why. Any thoughts?

TIA,
 
I think that if the one you've got works as it should and you can focus on the grains, then a more expensive one won't change anything for you. It's a pretty low-tech device.

What you should remember to do is to place a dummy sheet of paper of the same thickness as the real one you're going to use under the grain focuser as you use it. Otherwise you'll be focusing for the baseboard, not the paper.
 
One big problem with focusing scopes of nearly all designs is that it is difficult to use them in the corners and along the edges of the image. This is important as you need to check for focus in those areas to confirm negative flatness.

When I was doing a lot of darkroom work I had a focus scope that was "baseless" ... that is, the body narrowed to a point at the bottom. Hence it wouldn't stand on its own, but you could put the point anywhere on the paper. I don't recall the manufacturer of this scope nor do I know if it's still made, but I'll do some searching. This one is the same concept, but implemented differently and I've never used it.

Another thing that is important to me (aside from adjustment/alignment) is magnification and brightness. I want the largest magnification that is practical, as well as a bright image. This is because I would always check focus at working aperture, not just with the enlarging lens wide open. This eliminates any focus shift/deviation between wide open and stopped down.

Earl
 
Peak are excellent. I have moved up from the base model (which is very good) to the top-of-the-line model, which is wonderful, especially for looking at the edges of the projection. BTW, Micromega is just a Peak grain focuser with an Omega badge. They were cheaper on ebay because bidders did not know this little secret.

I have a Peterson. It works. But so does a Holga (and folks still buy Leica).

Does it mean I have sharper prints because I have a more expensive grain focuser? I don't know. But I enjoy using it more as it is easier to use.
 
Ive tried a few different ones, but find the Magnasight far and away to be the best and easiest to use. It has the nice wide viewing area to easily see your grain.
Bestwell-Magnasight-Grain-Focusing-Scope_W0QQitemZ180058952023QQcmdZViewItem
 
My preference is for the Bestwell Microsight grain focusers. I have used them for 20 years and never had a problem. I like the fact that you tune them to your vision with the cross hair in the finder for greatest accuracy. No other focuser I know of does this.

Somebody made the point about enlarger alignment, and of course this is very important. But this should be sorted out as a separate issue. If you measure and calibrate your film, lens, and paper planes, and they are all parallel as they should be, you won't have to check every print with your grain focuser. I place mine in the center and focus, knowing that everything is properly aligned.
 
Another basic technique, this time for enlarger head and baseboard alignment:

Take two mirrors. Scrape a small hole into the silver coating on the back of one of them in the center. You should now have a mirror with a very small transparent spot on the middle. Put this into your negative holder, face down, with the hole in the center - the placement of the hole and ideal size of the mirror depend on your enlarger model and the geometry of the negative holder. Put the other mirror on your baseboard, face up. If you now switch on your enlarger, you should see a dotted line of reflections on the mirror. (This actually works better if your mirrors are bad.) Also you should see a dot of light somewhere on the ceiling or on the baseboard. Now tilt your enlarger head until the line and reflection disappear. This happens if and only if the light from the dot gets reflected right up into the hole on the mirror. Voilà, your enlarger is now aligned.

Philipp
 
If you have to ask, then I think the answer is likely 'no'. It is fairly easy to judge the quality of your ability to focus the enlarger by printing from a film with a moderate and visible grainularity.

In response to the poster above who suggested ensuring that you're focusing on a piece of paper the same thickness as the paper you're printing on... in my experience, that is definitely not enough to make a difference maybe unless you are printing with your lens wide open. It is the surface of the film that is crucially important to have perfectly parallel to the lens, not the surface of the paper.. in the same way that it is so important inside the camera. I've found a decent amount of leeway at the easel end of things...

And I also find that in the event of prints being out of focus, it's either my fault for not focusing correctly or it's the result of the negative not being flat. This can occur when the carrier has been filed out too far (or you're using a carrier for a larger format) or if the temperature in your darkroom is especially cold. The amount of heat generated by the light source can be enough to manipulate the properties of your negative.
 
Bought my Micromega grain focusser 25 years ago. It has a hefty all-metal construction that makes the Paterson versions feel like Tupperware. The long mirror does allow a precise view throughout the frame. It also has a reticle, which would seem essential for direct observation of the aerial image.
 
tblanston said:
In response to the poster above who suggested ensuring that you're focusing on a piece of paper the same thickness as the paper you're printing on... in my experience, that is definitely not enough to make a difference maybe unless you are printing with your lens wide open. It is the surface of the film that is crucially important to have perfectly parallel to the lens, not the surface of the paper.. in the same way that it is so important inside the camera. I've found a decent amount of leeway at the easel end of things...
Click to expand...

Hmm- this is curious. There seem to be two seperate points conflated into some confused mis-information here. First, it is indeed beneficial to focus with the grain focuser resting on a piece of paper of the same stock (or at least thickness) as you will be printing on. Not doing this robs your print of the sharpest focus it could have, by putting your point of focus slightly behind the surface of the emulsion. True, depth-of-field might compensate, but I don't like that sort of lazy gamble in my prints.

Second is the issue of alignment. Shooting and printing have entirely different needs in terms of alignment of subject/lens/film planes. As any view camera photographer can tell you, it is sometimes desired to have these planes out of parallel while shooting; in general, printing is an entirely different matter. If any one of these planes is out of parallel with the others, it will diminsh sharpness in your prints. Sometimes this effect is desired, just as it is when employing view camera movements. However, leaving aside this sort of special effect printing, if the paper plane is out of alignment with the film and lens planes, you will get prints which suffer due to part of the paper being out of the plane of sharpest focus. Sometimes this is so slight that agan, d.o.f. might cover for you- but it might not; either way, your prints are still not as precise as they might be.
 
Checking focus in the corners can be tricky with the Paterson, but judging from these comments, I guess there is no reason to get a different/better one -- thanks!
 
I picked up a second hand top of the range Peak model i think it's the 3 or the 1 - the top part is adjustable and the bottom mirror is long and you can set it up to focus on the edges of the frame. Best £90 i ever spent for the darkroom. This in combination with a Zig Align enlarger tool (allows for the lens, negative and baseboard to be all set parallel) enables sharp edge to edge prints .
 
Hi, as a darkroom newbie I was happy with my small grain scope. This was difficult to use when the enlarger head was high (arms not long enough), so I managed to get a tall Paterson unit. I was a little alarmed to see that the two scopes gave me different focusing points, as if set up with one, some fine adjustment was needed to get it to focus with the other. This was a puzzle until I found that I could set up the scope by adjusting the focus on the wire at it's front or middle, giving minutely different focus points. I cannot see a difference in the prints, and wonder if exposures a couple of stops closed from the widest has enough DOF to swamp such small errors?
 
You must log in or register to reply here.
Back
Top Bottom