Sony NEX-series monochrome conversion, getting started

Go here to see general information about monochrome conversions

My first full frame conversion is now complete


THE IDEA:

  I've taken it upon myself to attempt a digital conversion of a color camera to a monochrome one. I first saw images somewhere on the net and thought of how much the images looked like film, and the detail and resolution were incredible. I decided that I had to have one. Most conversions were of Canon and Nikon cameras, but I love the mirror-less format. And I wasn't about to pay $9.000 for the Leica version, even though I did consider it for a few seconds, so it was off to the work bench. 


THE PROCESS:

  I purchased a SONY NEX-3 camera body on eBay for around $100. I figured this was reasonable enough to spend on R&D. After three attempts I had some success, but it was not really usable--there were some dead pixels and a few dead rows of pixels along the top. Not quite a success, but not a total failure either. The method was a mechanical one, and a bit too harsh for the sensor surface. I did not try any chemicals or acids up to this point, but was considering it. I went through 2 NEX-3 sensors before I had this mild success on the third. I didn't continue working on this project, thinking that the effort was too great for the gain. I had run out of ideas, and had other things to work on, so to the shelf. But then...


First relatively successful conversion attempt during the R&D stages of a Sony NEX-3. No processing applied

  …in one of those lightbulb-above-the-head moments, I came upon the solution and immediately tried it on a NEX-5N sensor with great success. It was perfect; no harsh chemicals, acids or special machinery of any kind was used. I've converted four sensors thus far, and the success rate on these conversions so far is 100%. I can now convert one of these APS-C sensors in about two hours. That does not include the disassembly/reassembly of the camera, which varies by model. I've taken apart and reassembled the NEX-5N so many times now, I can completely reassemble one in about 20 minutes. 

That first converted NEX-5N camera now belongs to a friend of mine, and he loves it. I've converted a total of 3 NEX-5Ns and 1 NEX-6. Both the 5N and 6 have the same identical sensor and are interchangeable. I'm looking forward to converting a full-frame sensor camera. I plan on converting the Sony a7r, which is a 36 MP full-frame sensor. I can't wait to see the results of that conversion. 

  One nice thing about the mirror-less cameras is that you don't have to worry about messing up the focus calibration, because there is none. The sensor does the focusing; meaning, when you see the subject in focus on the screen, it's in focus. No complicated calibrations to regain accurate focus. And the sensor also determines exposure, not some small sensor in the mirror box of a typical DSLR, so there are no issues there either. 


THE RESULTS:

first shot NEX-5n-1.jpg

First shot just after conversion.

  The photo at right was taken with the converted 5N camera just after the conversion. Click the image for a full resolution version. Because of the aperture used, this image has a shallow depth of field. It took about three hours to remove the CFA on this APS-C sized sensor. I used a Nikon 50mm ƒ 1.2 @ 5.6, 1/10 sec, 100 ISO with the Sony-Nikon adaptor I made (see link HERE) with ambient room light, which was a daylight balanced fluorescent tube. It was taken simply as a quick test, but I was very happy with the results. This was a complete and clean conversion. With this lens and sensor combination there is a 1.5x crop factor, so the image uses only the center portion of the lens' field of view. 


ANTI-ALIASING FILTER & FULL-SPECTRUM CONSIDERATION:

Two definitions: 

Anti-Aliasing (AA) filter & Low Pass (LP) filter are interchangeable terms. These filters are used mostly to reduce Moire effect, but have the effect of blurring the image slightly.

IR Cut filter, Hot Mirror & Color-Colrreccting (CC) filter are also interchangeable terms. These are used to mimic the response of the human eye across the sensor's sensitivity. The sensor "sees" more than the human eye does, so this filter reduces that response to that of our eyes. 

CFA half removed

RGB half removed-1.jpg

White bal. set to the color side

  With this camera there are two things to consider beyond the monochrome conversion. The first is the anti-aliasing filter used to prevent Moire effect. The other is the CC filter. On this camera they are combined into one filter sandwich, and it is easily removed. Most conversions you see advertised on the net for IR conversions are just that; the removal of the AA/CC filter. After the monochrome conversion, I did not put back that filter, because I wanted to increase the resolution as much as possible beyond what the monochrome conversion did alone. To gain back the color correcting I used an on-lens filter by MaxMax.com--the X-Night CC1. It's a simple matter to leave the filter off when taking a photo, so this gives me many more options than the stock camera. The more that I use this camera, the more I find that the CC filter is not so important. This is after all one of the reasons why the camera is more sensitive. The other reason is because of the removal of the RGB Bayer layer from the sensor. 

  Concerning sensitivity, testing shows that sensitivity is increased by about 10% by removing the BAYER patterned Color Filter Array (CFA) layer from the sensor. This was tested using a sensor in a NEX-5N that is half stripped right down the middle--half color, and half monochrome. The color cast on the right side is due to the camera's processor thinking it's seeing color information. The color cast is easily removed by sliding the Saturation slider to the left in most all editing applications. 

  I've determined more accurately that the EV difference before and after the conversion of this Sony sensor is +1 EV. I used RawDigger as my measuring tool to measure the values on either side of the half converted sensor. The lighting was evenly lit on a gray card, and exposed to just below clipping--exposed to the right. The small square in the image below near center is the area of measurement for the color side, and it was moved just to the other side of center (monochrome) for the second measurement. This sensor is currently open to the environment with no other filters between the lens and sensor. I also tried the same experiment without using a lens and achieved the same results. 

Half converted sensor; Color on L, Mono on R

  The values taken from RawDigger were calculated as shown below. 

Screen Shot 2017-03-18 at 1.25.52 PM.png

  This increase in EV is due to just the removal of the CFA and not of the CC or AA filter; the effect of those two filters is equal across the entire sensor. Leaving those filters off does, however, increase sensitivity slightly by allowing more light to fall upon the sensor. More information about that here. It seems that the wide variation in the readings on the color side is due to my gray card not being entirely neutral. 


  The two photos below were taken with the second converted 5N, with and without a CC filter. Both were shot without the AA filter in place. The first had a CC filter over the lens to remove UV and IR light. The second was shot without the filter. You can notice a slight increase in dynamic range, or opening up of the shadows. Look at the bamboo spoons and the lens of the FE2 in each photo. Also note the shadow under the plate. Please click on the images to open them in a new window, then click again for full resolution at 1:1. You can then compare them side by side. If you look closely at the rim of the SS utensil holder, you can see some fine dust and lint--time for some house cleaning. The label of the bottle is quite sharp also. Notice the subtle gradations of shade in the glass and spoon, and the black leatherette on the camera. Very little post processing was done to these images. In LightRoom the settings were to remove the color cast, clarity set to +20, and USM was set to +70. Exposure was optimized in camera to avoid adjustments in LR. 

  I used an E-Mount Sony 50mm 1.8 lens @ ƒ8.0, 100 ISO. An Alien Bee studio flash set to low power in a beauty dish was used to illuminate the scene. (Open one of the images in a new window to compare them side by side in full resolution).

Shot with IR cut filter

  These two photos show that the extra red (IR) light increases sensitivity, and change how some colors are rendered. Notice the change in brightness of the bamboo spoons in the two images. The spoons have some red in them and reflect more IR light, so they are brighter. As a side benefit, the Sony has a Creative Style setting of B&W, so the image on the LCD shows up as monochrome. This allows me to see in B&W, as it were. A very handy feature, something that was not available back in the film-only days. And the use of traditional B&W filters can be used to increase contrast in the images, and is required since there is no individual RGB color information present in the file.

Shot without IR cut filter

  Since the processor in the camera "thinks it is seeing" color, the images come out in RAW format with a magenta cast. This is easily taken care of in post processing by sliding the saturation to zero. You could do this same conversion with a conventional color image from an unconverted camera, but removing the Color Filter Array (CFA) from the sensor increases both resolution and sensitivity, and this was my main goal in this project. This camera behaves like a B&W film camera now, and I like it that way. I have a lot of experience shooting film, so it's familiar to me. And the slight increase in resolution and the +1 EV increase in sensitivity is really nice. I've purchased a standard set of B&W color filters for shooting with this camera. I also plan on getting more IR filters to give B&W IR photography a try.


COST CONSIDERATIONS:

  I've converted four cameras to date; 3 NEX-5Ns and one NEX-6. All four conversions came out perfect; no dead pixels or remaining RGB filters on the sensor. The next step will be to convert a full-frame sensor camera. I will convert a Sony a7r for my first attempt. At 36 MP, that should look very good indeed. Come back to see the results of that project. 

  One of the main reasons I wanted to do this project was to save on costs. But I'm also of the mindset that if I see that someone else can do something, then I figure so can I. I was not about to buy a $8,000 Leica Monochrome camera just to take digital B&W photos. And considering the reviews of that camera, I didn't feel it was worth the cost. I'm not one of those die hard Leica fans, and I am practical in regards to my gear. Tools are important to any endeavor, but money alone can't make a good image. 

  Digital is so convenient, and some of the results I saw across the net of monochrome converted cameras were really impressive. That's the main reason this project got started. So I feel that the cost and results are well worth the effort I put into this project. As I said above, I am going to do a full-frame sensor real soon, and can't wait to see the results.

a7r conversion.jpg

  The full frame conversion is now complete. Go here to view that project

Go here for more information about monochrome conversions.

Go to my contact page with any questions, or if you care to comment. 

© Daniel Morrison 2014