I’ve been slowly making progress on the VC LED head. I choose to tackle this as two separate steps; the head and the controller. What you see here are the two pieces of the head resting on the baseboard of my Durst 138S. I choose this configuration to allow me to quickly switch from this diffusion light source back to the original condenser head. What I did was take two scratched condensers and removed the glass. One was a 240mm and I used it for the top part (bottom in the picture). Into this I drilled two holes on the front for 6pin Din connectors. On the inside I mounted a sheet of 1/4″ aluminum for a heat sink and support for the LEDs. This is held in place by the original Durst screws and some aluminum tubing over them cut to fit snuggly. In the other condenser shell I mounted a piece of 1/8″ translucent white plexiglass, which is held in place with white foam core around the edges. First I needed to cut some of the metal from shell since this was for a smaller 130mm condenser. A metal blad in a jig saw made quick work of this since the shells are aluminum.

The LEDs are Cree XP-E Green for the soft light and Cree XT-E Royal Blue for the hard light. There are 12 of each arranged in two banks. This arrangement was chosen based on the capabilities of the controllers I am using. I originally was going to go with a Mean Well 60-48D which could drive all 12 LEDs in each bank, but I found it didn’t dim quickly enough to allow the dimming feature to turn the lights on and off. After a bit of research I settled on using A009-D-V-1000 BuckBlocks, which offer a lot of options for control, and respond instantly to dimming commands. The only issue is they don’t have enough forward voltage to drive more than 6 or 7 of these high power LEDs.

I was originally only going to have one cable to feed power to the head, but I found out the hard way that each BuckBlock must have it’s own ground wire along with hot wire, so my 6pin Din connectors don’t have enough pins for all the needed wires. For reference when I hooked two of the controllers up with the negative wire as common when one was dimmed the excess current is fed into the other bank of LEDs. When I checked 2A were flowing through my 6 green LEDs (rated for 1A maximum). They still work, but I do wonder how much of their life I used up in the minute or two it took to figure out what was going on.


Right now they are hooked up a bank of 4 10K potentiometers. This allows me to adjust the brightness of each bank for testing purposes. The head is even to less than 1/3 of a stop across most of the surface. The very corners are about 1/3 stop dimmer than the rest. Given the arrangement of the LEDs I can adjust (in software) to bring the far edges and corners up in relation to the center. Doing this gets me a very even light source. On the baseboard (factoring in lens falloff) it’s even to about 1/5 of a stop. I might be able to tweak this more, but it’s better than any of my other enlargers, though I haven’t made any prints with it yet.


I think I may want to get some right angle connectors for the cables. I’d also like to get a more flexible wire for the cords. But other than that I am pretty happy with this first phase of the project.

I have also been experimenting with the Arduino based controller for all of this. The BuckBlocks can be controlled with a PWM signal and a simple 2N2222 transistor (see their data sheet for wiring diagram). This should make wiring up the system fairly easy. They also respond instantly this way from off  then to fairly dim up to full brightness.

I’m still working on the software and board design, but I’ve checked a preliminary version of the controller code into GitHub. This is based on William Brodie-Tyrrell’s F/Stop Timer. This is very preliminary, but I’m trying to get it working in both a split grade and integrated mode. Feel free to fork the code and send me a pull request if you want to add a cool feature.

I have been printing with the condenser head on my Durst 138S. I use Ilford multigrade filters in the filter drawer for contrast control. I like the sharpness of the grain that the condensers give, and there’s something satisfying about sliding the correct condensers into the slots, due I think to their heft and how well built the machine is. But, and there’s always a ‘but’, when I want to make use of a dodge and burn mask I can’t. This is an inherent limitation of the condenser system which essentially focuses an image of the light source (bulb) through the negative and into the center of the enlarger lens. This collimated light is what’s responsible for the perceived sharpness of the prints. But it means that adding a diffusion layer as needed by the dodge / burn / pencil masks breaks the design.

I tried various methods of diffusing the existing light, but the results were wither too dim for large prints, or too uneven. So I decided to build my own light source. I had used white LEDs to make a simple head before, which worked pretty well. It was simply a bank of high power LEDs and a constant current controller which plugged into a timer. I thought about rebuilding this to fit the Durst. But given it’s a 5×7 enlarger I can’t find contrast filters large enough to fit above the negative, and I wanted to avoid under the lens filters (partially since the current set isn’t big enough to fit under the 210mm lens I have). I also enjoyed being able to set the contrast in finer steps than 1/2 a grade when I was using an Ilford 500 head on the 4×5 Omega.

So I’ve decided to build a variable contrast head. This will use two colors of LEDs; green for the soft grades; blue for the hard grades. By varying the intensity between them I should be able to produce any grade between the two extremes.

Parts have been ordered, and I’ve been playing with the LEDs and controllers. I’ll post some updates soon.

I scanned the users manual and the service manual for the Durst Laborator 138S enlarger in case anyone else needs them. I haven’t seen the service manual posted online before, and the instructions are a different version from what is posted at Durst Pro. Hope these help someone.

Durst 138S Service Instructions

Durst 138S Instructions

edit: Here’s one more version of the instructions

Durst 138S Instructions – V2


About a year ago I bought a Durst Laborator 138S enlarger to handle 5×7 negatives. The enlarger I bought showed signs of heavy use, and seems to have come from a university darkroom. I would have sent it back, but the freight shipping cost as much as the enlarger. So I set about replacing some parts that turned out to be missing, and a few that were very worn such as the stage for the negative carrier and bellows. It took about 4 months but eventually I had a nicely working 5×7 enlarger.

So why did I just buy another one? I don’t know.  I found one on ebay within a day’s drive for a decent price. It’s a complete package in excellent condition. The condensers are pristine, the negative carrier is in nicer condition than the one I picked up for the other 138S, and it’s of the newer style that can take a lens turret or a large lens plate. It also has a couple of original Durst bulbs in various sizes.

I picked it up last weekend and now the my office is filled with Durst parts as I decide how I’m going to fit it into the darkroom. I haven’t decided if I’m keeping the old one too and retire the Omega D5 enlargers, or if I’ll replace the older Durst with the new one and keep the Omegas going for color and to use the Ilford 500 head. Maybe I need to build a larger darkroom 😉

The seller of the Durst was winding down his darkroom usage so I also picked up a few other items including a Micromega grain focuser, Harrison changing tent and forced air print drying unit that he was selling.

I talked with a nice Sigma rep and he gave me the option of sending the lens and camera in to them and they would adjust the lens to match the camera. I thought about this for a bit and decided against it. The main reason was the cost. I could send the lens back to B&H for no charge, or I could pay to ship the lens and camera to Sigma. With insurance this was going to run around $65, and I would not have the use of the camera for a week or so. So I sent the lens back to B&H. If I was near the Sigma service center bringing it in would have been the easy choice.

Rather than wait for another possibly defective lens to arrive at B&H and then get to me, I called Hunt’s Photo in Manchester NH. They had a lens shipped up from the Boston store. Today I went and briefly tested it out. AF seemed accurate at all distances. So I bought the lens.

I went for a walk around the village with it once I got home to test it out. I have only briefly looked at the pictures, but in going through them I feel the AF performance is acceptable even at f/1.4 and all the distances I tried. This weekend I’ll take a little more time to see if AF fine tuning will help, but at first glance it’s working fine without it.

When I started the walk I remembered the opening conversation I had with the Sigma rep. He initially thought I was calling to report an issue with the side AF points not working. I explained the issue with distances and he dropped the subject of the side AF points. This was also mentioned by another person in this thread I started on photo.net. In theory Sigma will have a fix for this soon.

So I also tested out the side AF points on a few shots. I think my results on this are inconclusive. Some of the shots seem off a bit using the side AF points, and a few seem OK. I will need to do a more controlled study. But for the time being I can live with just using the central point and recomposing. It’s still better than my results with manual focus and a fast lens on this camera.

When I saw the early reviews for the Sigma 35mm f/1.4 DG lens I though it had a lot to offer me. 35mm is probably my favorite focal length for general photography. Reviews praise the lens for how sharp it is wide open. It also seems to have decent bokeh (out of focus rendering). I have been using a Rokinon 35mm f/1.4 lens on the D800E since I bought the camera last spring. I am really happy with the image quality of the Rokinon, but I have lots of trouble achieving perfect focus with it since it’s a manual focus lens and the D800E has a screen that’s not very good for manual focus. This really limits my use to the tripod and Live View focusing. So I ordered the Sigma, even though it was on back order.

Last Thursday it arrived. I quickly did some indoor focus tests and like all the other lens on this particular camera it seems I needed no Fine Tune focus adjustment. Cool. But my tests were done inside at close distances. We got some snow that evening and then is stopped midmorning Friday. I went out for a walk at lunch, despite the ugly gray sky. I brought a tripod to do a few tests to see if the lens was obviously decentered, and also just shot a lot of hand held shots around the village, since this is how I hope to use the lens much of the time. On Sunday I went to my brother’s house and shot a few pictures of his dog (and the rest of the family, but I won’t put them in this post), again hand held.

Upon review of the images I found some were perfectly in focus, and some were way off. I noticed the close up ones were good, and the more distant ones were soft. So I shot a lot of tests in the backyard and found that with the lens adjustment at 0 the auto focus was right on for close distances, but infinity was way off.  I adjusted for infinity which requires a -11 for the Auto Focus Fine Tune. Close up shots are now noticeably soft. I’m not sure what to make of this. Sigma will be making a USB dock and software to adjust the focus points, so maybe this is the solution. But it’s not available now, and I don’t know when it’s coming out. It also seems crazy that we need to spend more money to make our lens work as it should. I haven’t decided if I should send it back to B&H and wait for another copy to come in, or send it to Sigma for repair.

Here’re a few examples:


Full image. Focus on hanging sign.


Focus point


Background that’s more in focus than focus point.


Full sized shot of mailbox. Take fairly close up. Focus point on red flag on front.


Focus point on red flag. I’d say it got pretty close.


Close up shot with focus point on left eye. f/4


Left eye. Again the close up focus is good.

There are a few more shots over on my SmugMug gallery. Most are at f/1.4 to show the focus errors more clearly. There are a few shot stopped down. It’s pretty amazing how well corrected this lens is at wide apertures. Over all I am pretty happy with the image quality. It’ll certainly take many more shots to learn the lens. But sadly it doesn’t look like I can trust the Auto Focus, so is it really any better than my manual focus Rokinon?

The full frame of my son, William, sitting on a slide. Delta 400 film shot on a Nikon N80. Unsure of the lens. Digitized with the D800E and Rodagon D 75mm f/4

The full frame of my son, William, sitting on a slide. Delta 400 film shot on a Nikon N80. Unsure of the lens. Digitized with the D800E and Rodagon D 75mm f/4

I have many rolls of 35mm black and white negatives and color slides that I have never printed, and never scanned. I also have boxes of color negative film, but luckily we had lab prints of these. Even better most of these rolls have the prints with the negatives. Most of the 35mm film pictures are record type shots taken to remember an event, a look, or just because. The bulk of these are from the period right after when my kids were born up until I bought my first digital camera.

I’ve had a small darkroom for a while now in the spare bathroom, but I only printed a small fraction of the pictures I took, and then only the ones on black and white film.

I wanted a way to print the color slides I took, and I wasn’t prepared to start color printing in the darkroom at that time. So when the Canon FS4000US scanner came out in 2001 I bought one. It was a cheaper competitor to the Nikon scanners that I really wanted, but I could afford the Canon. The scanning was reportedly of the same quality, but it reportedly wasn’t built as well and lacked the ability to batch scan. I also think the film holders were not as good. Despite these negative points the experts all said it was an excellent scanner for home or light professional use. Combined with the new photo inkjet printers I was set. The quality at the time was very satisfactory. I could significantly crop and still make nice 8×10 prints.

For new film I scanned a few frames from each roll that I thought I might want to print or share online. But scanning a full roll took too much time with this setup. I still made contact prints of my black and white film in the darkroom, and continued to get lab prints from the color negatives. The slides got viewed and maybe a few scans were made. But mostly all the film sat in binders, to be tackled another day. Sadly only the lab prints got any significant viewing. There were also many rolls from before I got the scanner that I never went back through. Needless to say I have a whole lot of images I haven’t seen in the last decade, and most other people have never seen.

Fast forward 12 years. In that time I bought a digital camera, or 10, for the record type pictures and moved my art photos to a mixture of medium and large format cameras. I also have a fair number of record type pictures on medium format film as well. The digital images are easy to view, and I enjoy going back over them in Lightroom. Most aren’t technically great, but there’s enjoyment to be had watching my kids grow up again, or remembering a trip or just a simple hike.

Last summer I bought a PB-4 macro bellows for my Nikon D7000 to use for macro. The idea was only to get the movements of a view camera for flowers and such with the DSLR, since the bellows had limited tilt and shift capabilities. But it arrived with a slide copy attachment, which got me thinking. So I tried it with a 55mm AIS macro lens and some slides. The results were pretty good, at least in the center. About on par with the Canon scanner. But it was fast. About 15 minutes to scan a roll of 36, and I could probably go faster. I put it aside though because the quality on the edges made it difficult to justify the time to scan a bunch. But it really had potential.

Going through the contact prints and slides looking for a few images around Christmas last year I got to thinking how much I wanted all the old images moved into LightRoom as well. But the thought of scanning them on the FS4000US is not something I am looking forward to. As I see it I have a few options:

1) I could scan them on the FS4000US. I used to run the scanner on a Windows machine with a SCSI card. But my MacBook Pro doesn’t have a SCSI card. The scanner does however support USB1. The shipped software is incompatible with modern systems, but surprisingly with ViewScan the scanner is still fully functional on the latest Mac computers (and probably Windows). But with the USB1 interface each scan takes about 10 minutes. However Viewscan can be setup to automatically scan all the images in the holder. So 4 slides, or 6 negatives, at once can be done. I can do other things while the scanner does it’s thing.

2) I could buy a faster and better scanner for bulk scanning. I have looked at a few other scanners on the market, but none really look much better than what I have. A few will batch scan uncut rolls, but mine are all cut. I could buy a Nikon LS5000 with a slide feeder, but that only covers the slides and is expensive.

3) I could also send them out to be scanned, but that’s cost prohibitive and I don’t want my film sent over to India as the more affordable places do. But time is money, and ScanCafe seems to get decent reviews online. At least Ken Rockwell seems to like it. At $0.22 a scan that can add up fast. About $8 a roll, and I figure I have 400 rolls of film to scan.

A crop of the above image. Delta 400 film shot on a Nikon N80. Unsure of the lens. Digitized with the D800E and Rodagon D 75mm f/4. No sharpening was applied. Simply inverted with a correction curve in Lightroom. Exported using Photoshop CS6.<br />When the negative is evaluated with a loupe it appears the scan captured almost all of the information on the frame.

A crop of the above image. Delta 400 film shot on a Nikon N80. Unsure of the lens. Digitized with the D800E and Rodagon D 75mm f/4. No sharpening was applied (sharpening was set to 0). Simply inverted with a correction curve in Lightroom. Exported using Photoshop CS6.
When the negative is evaluated with a loupe it appears the scan captured almost all of the information on the frame.

4) Finally, I now have a Nikon D800E, and I’ve been playing around with the bellows setup again. I switched to using an enlarging lens instead of the Nikon macro lens since the sharpness was better. I further found out there are lenses designed for 1 to 1 copying. I just got a 75mm f/4 Rodagon D, and it’s incredibly sharp across the entire frame. I think this combination of a full frame camera and a lens optimized for 1 to 1 reproduction really works well.

I am going to see how fast I can get with the DSLR and the bellows. I know it does a good job with both the black and white film as well as the color slides. In fact the slides scan cleaner on the D800E than on the scanner. I haven’t compared it to my drum scanner, but at first glance they look to have less noise than that as well.

In a future post I will write up how I do the scanning. I hope to document the process for myself and others. I also plan on working out how to handle color negatives. I’m pretty sure they can be made to scan well with the DSLR. I also plan on scanning a reasonable sample size of the film I have to see if there are any issues, especially if trying to do it myself is penny wise and pound foolish.

And just for fun I’ll show the same negative scanned on the Canon FS4000US, the D800E, the ScanMate 5000 drum scanner, and even an old Epson 4870 flatbed.

Stay tuned…

I guess every blog needs a first post, so here we go. My name is Larry Gebhardt and I’m an avid, but amateur photographer. By trade I’m a software developer. This blog will contain a mix of things that interest me, mostly related to photography.

I work with both digital and film cameras. These range from cell phones, digital point and shoots, and high end digital SLRs and from toy film cameras up to 5×7 large format sheet film cameras. I also print both in the darkroom and by scanning and inkjet printing. I spend way to much time experimenting with equipment and processes and not enough time getting out and taking pictures.  I’m hoping to write a bit on how I plan to pare down my overly broad collection of cameras. Maybe writing that here will force it to happen quicker.

I mainly consider myself a photographer of things. I like landscapes, cityscapes, macro, wildlife and nature photography.  I also like street and portrait photos a lot too, but I don’t feel as comfortable shooting in those styles. I guess that’s a side effect to being inclined towards introversion.

I tend to ramble, so that’s probably enough for now.