bruce_ellingson Posted August 21, 2000 Share Posted August 21, 2000 Hasselblad users, During the past year I purchased a used 501 body, a used back (which I had refurbished), an 80mm (C t*) and a 250mm ©. After returning from a recent trip to Yellowstone, I discovered that my Velvia images seem uniformly soft. Even landscapes shot at infinity with the 250mm were soft. A recent test, crudely and quickly done in B&W, seems to indicate that both lenses are giving me less than the razor-sharp images I have come to expect of my Canon 35mm gear. Three questions: Have you tests to recommend that might help me pinpoint the exact nature of the problem? What might the source of soft focus be if it appears in images photographed through both lenses? If both lenses test soft what are my next steps? Thanks, Bruce Ellingson Storm Lake, IA Link to comment Share on other sites More sharing options...
colm boran Posted August 21, 2000 Share Posted August 21, 2000 </html> <body> I assume you were using: <p>1) A substantial tripod <br>2) A cable release <br>3) Mirror Lock Up <p>If you had the lens(es) focused at infinity and were shooting subjects far enough away and the images are still soft, I would rent or borrow another film back. Try the same shots with both backs and then compare the results. Perhaps your film loading technique is not exactly correct? Have someone else (sales guy?) show you how he/she loads film and compare to your procedure. Maybe this could lead to film not being completely flat? Don't really know since I've never experienced this problem on my 500 C/M. </body> </html> Link to comment Share on other sites More sharing options...
mel_brown1 Posted August 22, 2000 Share Posted August 22, 2000 I'm not a Hasselblad user, so mine are generic suggestions. Because both lenses failed to deliver, I agree with Colm that you should first try another back. You could try some shots of a brick wall or a newspaper, shot at an angle with the lens wide open or one stop down. Tripod, lock-up, and cable release, of course. Lack of film flatness is a possibility, but should not affect all frames, especially if the entire roll is shot in a short period of time. Film bowing will be worse near the center of the frame, so you might try some focus bracketing of a distant object, moving off the infinity mark in very small increments. If the first shot is sharper at the edges than the center, the film is likely bowing. That could be caused by something so simple as insufficient tension on the supply spool. Most camera makers offset the base focus outward just a fraction of a millimeter to compensate for the average film bowing distance. Could be that yours is not set just exactly right. Link to comment Share on other sites More sharing options...
victor_randin Posted August 22, 2000 Share Posted August 22, 2000 Bruce,I guess that unsharp images may be out-of-focus reason: 1) The angle of the mirror is incorrect (you may compare focusing a subject on infinity when placing it on the top and then on the bottom of the screen, both of focusing must be equal). 2) The back (A12?) is unadjusted: unmatched insert, loose pressure plate, and therefore incorrect distance between lens seat and film plane (74,9mm).You could make some visual control. The camera with the lens and the back is on the tripod. The wide-open lens is set on infinity. The insert is out of the back. A ground glass (about 2 ¼ X 2 ¼) is placed on the place of the pressure plate and slightly but very correctly pressed with two finger of the left hand to the inner frame of the back (ground surface to the lens). Under some angle from the left side (with a loupe of x4 - x6) you could see reversed images (aerial wires, roofs) on the left part of the ground glass. So, you may control the sharpness of the images in the center and in the corners. That is enough to draw the conclusion about how the back is adjusted and matched to the body (but without the insert). With the insert the pressure plate-to-frame clearance is to be zero.Best. Link to comment Share on other sites More sharing options...
gene crumpler Posted August 22, 2000 Share Posted August 22, 2000 I recently got a used 500CM/80mm/A24 back. I found that the focus was off when focusing with the ground glass (it was immediately obvious from the mis-match of the scale and ground glass focus at infinity). I confirmed that the focus scale on the lens was dead-on by shooting a test chart with the lens at f2.8 and measuring accurately the distance from the chart to the film plane marker on the back. So I just did a little shimming with little pieces of tape on the bottom of the screen to get the ground glass to match the scale focus. Was the focus OK when you tested the camera after you bought it and did both lenses suddenly become become unsharp on your trip? Does the focusing scale on both lense match up with the focusing in the view finder? If not then you have a problem with the screen or perhaps the mirror which may be a quick fix. If both the screen and the scale match with both lenses, then you have a problem with the film placement (back). Can you borrow a back and see if this is the problem? A little detective work should locate the problem. Link to comment Share on other sites More sharing options...
gene crumpler Posted August 22, 2000 Share Posted August 22, 2000 Be sure the paper leader goes under the chrome guide above the face plate. Link to comment Share on other sites More sharing options...
michael_heal Posted August 22, 2000 Share Posted August 22, 2000 <ol> <li>Are you using pre-release? Even if your tripod is unsteady, I doubt <em>all</em> your pictures would be soft.</li> <li>Do you put the film under the guide when you load the film? (As per Colm's suggestion.) If not, the film will sit too far forward, causing this effect.</li> <li>Next, have Hasselblad check that the mirror is returning to the correct position and that your focusing screen is aligned properly.</li> <li>If that is not a problem, rent or borrow another lens. You could also try focusing by measuring the distance instead of using the viewfinder. The marked distances on the lens are usually (but not always) extremely accurate. It seems unlikely that <em>both</em> lenses would be out of alignment, but it is possible, particularly if the lenses were abused or subjected to amateur repairs. If so, you must send them back to Zeiss. Note that even authorized Hasselblad repair depots do not have the equipment necessary to align lenses. They should, however, be able to forward them to Zeiss on your behalf.</li> </ol> Link to comment Share on other sites More sharing options...
Robin Smith Posted August 22, 2000 Share Posted August 22, 2000 Bruce Helpful suggestions above. Were you on a tripod and what were typical aperture and shutter speed settings for your shots? My guess is that you are suffereing from camera shake, but obviously we can't tell unless we know the exposure data. Robin Smith Link to comment Share on other sites More sharing options...
sean_finch Posted August 22, 2000 Share Posted August 22, 2000 Hi Bruce I recently got a used 501c with the 80mm CT* lens. All was well except the focus seemd odd. At that time I hadn't processed the film, so couldn't be sure if the images were soft, but the indicated distance on the focus scale looked out compared to my estimate of the distance (ie: what looked to me to be approx 3-4 metres was showing as 7 metres on the scale). Also the split image in the finder did not show correct focus at infinity. I returned it and compared it to another (almost identical) 501c body which focused ok. It turned out that the focusing screen was at fault. I could not see what the difference was, it was the right way up, in the right position, etc. I got the screen replaced and all is now well. It's possible that this could be the problem you have, the screen I'm using now is the acute mat D type (has two notches in the metal frame). Good luck Sean Link to comment Share on other sites More sharing options...
twmeyer Posted August 22, 2000 Share Posted August 22, 2000 I've heard something about the foam under the mirror aging and compressing which causes the focal point to shift out of position... t Link to comment Share on other sites More sharing options...
jeff_drew4 Posted August 22, 2000 Share Posted August 22, 2000 Or try this: Hassy with decent slide film on tripod, at a measured distance from a well-lit wall which has a sizeable piece of newspaper taped to it. Meter carefully, Focus on paper carefully, compare with tape measure, lock-up mirror, expose. Try same target exercise with all lenses, then a known but different camera. Were your 6x6cm slides better before Yellowstone? You already see the differences in format ie. resolution etc. The magnified image from 35mm vs. 6x6cm is where the Hassy should win. IMHO: smaller negs/slides look perceptibly sharper vs. larger ones due to the way we see and the info captured on the film. My Minox 8x11 negs appear sharper than my 6x7cm negs, but 8x10 inch prints argue differently. In fact, the resolution per mm for Minox lens vs. 6x7cm IS higher! So I get more confused and disregard the science stuff and blast away! :-) Link to comment Share on other sites More sharing options...
ken_eng Posted August 23, 2000 Share Posted August 23, 2000 I'm almost sure that your problem is mirror misalignment. I've had this problem and recommend that you send it back to Hasselblad and get it fixed. A test that you could try is to setup a yard stick so that it's facing your camera at a 45 degree angle. Focus at the mid-point of the ruler. Take a meter reading and set your exposure with the aperture wide open. Shoot your camera. You could bracket both shutter speed and aperture for more data, but all you really need is one shot. If you do bracket, take notes so that you remember what you did. Process your film and examine negatives with a loupe. This way you could tell aproximately where and how far your camera is focusing at, whether it be in front, or in back, of the plane of focus. If both lenses don't test consistently, I would suggest sending the whole kit-n-kaboodle back to H'blad for a CLA. That's gonna be costly! I think it was $125 for each body and lens, and $75 for each back. Hope this helps! Ken Link to comment Share on other sites More sharing options...
djphoto Posted August 23, 2000 Share Posted August 23, 2000 Bruce, the most likely cause of your problem is mirror misalignment. I purchased two used 500CM bodies in 1998 and both had this problem. The mirror on a Hasselblad actually rides in a shallow metal pan and rests on small, vibration-absorbing rubber discs. Over time the discs lose their elasticity, the mirror gradually sinks into the pan, and your camera is out of focus. I learned all this from Bill Maxwell, who realigned my cameras for me and installed his Maxwell Precision Optics screens (the best made, in my opinion) in both bodies. As far as I know, Bill is not yet on line but you can contact him at 770-244-0095. He is an extremely knowledgeable man, and is working on a book about how to maintain sharpness in cameras. Link to comment Share on other sites More sharing options...
jeff_drew4 Posted August 24, 2000 Share Posted August 24, 2000 Dave & Bruce et al: Thanks for the tips! I occasionally shop for used Hassy bodies (only when I'm allowed to, of course) and did not know about all the mirror position issues with older gear. Good stuff here! Link to comment Share on other sites More sharing options...
frank_ward1 Posted August 25, 2000 Share Posted August 25, 2000 Hi Jeff! Now to Bruce's question. Same thing happened to me with my old 500C. I made the mistake of driving around with it in my trunk. It bounced the heck out of the alignment. A trip to a good Hassy shop should clear it up in no time. Frank http://www.culturalvisions.com Link to comment Share on other sites More sharing options...
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