Hi all, I'm new to photography and I just started using my brand new Opemus 6a. Altough I find it very nice and easy to use I can't get a sharp picture whenever I try to enlarge more than a 9x7 size.

I tried with the minimu aperture but the light won't be brigth enough to affect the paper. (I use multigrade 4 rc)

Is it a problem with the lens or the enlarger or just with me !!!! ;-)

Thanks for your help, Stephane.

-- Stephane Thao (steph@santhy.net), September 03, 2001

Answers

If your negatives are well focused, then the problem is with the enlarger lens or with your ability to focus the image on the easel. Try another lens. If your prints are in focus, have the first lens checked by a competent lens technician or return it to the dealer. You might also try using a magnifier on the easel to allow you to focus on the grain. A proper lens should produce sharp prints at any aperture and any size.

-- Keith Nichols (knichols1@mindspring.com), September 03, 2001.

Stephane:

Enlarging lenses, like camera lenses, will have an optimum aperture that will give you the sharpest image. An old rule-of-thumb is that, in order to get the sharpest image, a lens should be stopped down a couple stops from the max aperture. That might or might not be true, though. You might want to check with the lens manufacturer about that. If the manufacturer doesn't make that information available, you can get a reasonable approximation by using a grain magnifier to judge by eye which aperture appears to be the sharpest. Usually the smallest aperture definitely is not the sharpest.

If the lens you are using is an inexpensive one, there is a very good chance that 9x7 (Are we talking inches or centimeters?) is the maximum that is acceptable to you. However, if you are working with the 35mm format, that image size might well be the max you will find acceptable no matter how good the lens is. A lot depends on how picky you are!

-- Ken Burns (kenburns@twave.net), September 03, 2001.

I use an older Opemus 5 model, and I've used an Axomat (also Meopta) before that. Both have a focusing aid, and I suppose the Opemus 6 has the same feature: Gently pull out the neg carrier until it locks in the half-inserted position. Then adjust focus so as to see one thin, straight, bright line on the easel. This should eliminate your eyes as cause of the problem. If you focus like that and the prints are not sharp, the adjustment of the focusing aid is off, or the negative plane is not where it should be. The reason may be popping out of plane through thermal expansion, among other things.) Then try focusing with a grain focuser. If, in spite of a clear image of the grain in the grain focuser, your prints are still blurry, you may be experiencing the grain focuser problem with VC paper reported by Ctein in Post Exposure (see that book for the remedy, too).

Check your prints to find out if they are just generally blurry, or if there is a sharp zone. If the latter is the case, negative plane, lens plane and print plane may not be parallel (or the negative may not be plane at all because of popping out of the plane). Alignment of enlargers is described in many basic printing books.

Remember to always focus at max. aperture (smallest f-stop number). Only stop down afterwards. (The only exception to this would be one of those few lenses that exhibit a focus shift on stopping down.) The best aperture should be 1,5 to 2 stops down from max. aperture, i.e. somewhere between 4 and 5.6 for 35 mm, or an f-stop more (smaller aperture) for MF. Stopping down beyond f/11 will degrade image sharpness due to refraction at the diaphragm.

Regards, Thomas Wollstein

-- Thomas Wollstein (thomas_wollstein@web.de), September 04, 2001.

I have an Axomat 5a and have managed to find several ways to insure out of focus prints.

Make sure all your convergance corrections are set at neutral settings. If they're not, something is out of line and you will have focus problems.

Also, make sure your lens board is fully seated. It's easy to get the lens board flange out of either of the two hold down nubs, and that will cause focus problems.

When I first got my latest Axomat, I used a really inexpensive lens but still got fine prints to 11 X 14, so I doubt it is your lens.

-- Gary Calverase (grcalveras@aol.com), September 06, 2001.

I know this sounds obvious, so please don't think I'm being rude... do you have the enlarging lens mounted in the correct side of the lens plate? 50mm lenses go in the concave side, 80mm lenses go on the convex side. This would certainly affect your focusing if you had it round the wrong way :)

Andy.

-- Andy Jones (adjones@mac.com), September 21, 2001.