Reikan’s Focal System- DSLR Autofocus Microadjustment Calibration
I need and want all of my images to be spot on tack sharp. So I spend the necessary time to make sure I get that from my photography.
The higher end DSLR’s today come with some kind of lens microadjustment. And there are lots of ways to calibrate your lenses using that capability. I wrote about all of the ones that I knew of about a year ago HERE.
But I found a new one…. and its REALLY Cool. In fact it’s the only method that I use now. Its Reikan’s FoCal System.
It’s AUTOMATIC or at least that is one of the options. There is some set-up required but no more than all of the other systems. After that just sit back and relax while it snaps away. You even get a data report at the end.
So let me tell you about the System and why I think its so great. I will also show/tell you about some tips about how to run the calibration.
So what is the system. Well there is no hardware….its all software. You need to have a decent printer and a PC or a Mac (in a week or so a Mac version is coming out). I think its better to have a laptop so that you can set it up close to the camera. You will need a tripod. Oh and your camera and lenses are necessary.
How does it work? Well this is my understanding of how it works. They have a target that has a lot of sharp edges on it. I think they somehow measure the total whiteness of the target. If the lens is not focused there will be blurring of some of those sharp edges. That will reduce the total whiteness. The software controls the camera by taking several shots at each each AF MA (micro-adjustment) point. A curve of the points of data is plotted of whiteness value (they call it Focus Quality) versus MA point. They are very secretive on how this all works so this is only a guess on my part. There is a peak whiteness point to the plot for a specific MA point…. And there is your final MA setting.
The software keeps track of any light changes that have nothing to do with the MA adjustment. This is important in that if you are using sunlight or indirect sunlight or CLF lighting. There can potentially be light shifting. Also if there is not a good curve fit as it traverses the MA spectrum it will ask you to run more data points. The program can also run focus points off center. It can run wide and telescoped calibrations on zoom cameras. It also has a tool that will run a lens through its different aperture values and tell you the sweet ( aperture) spot.
I am an engineer by profession and I gotta tell you that this software is REALLY Cool.
Can I trust it?
I think yes. I went back to the Lens AlignPro system the I was previously in love with and reran the cal on that and got the same result. But I realized then that there is a lot of quasi qualitative judgement going on. In the visual systems you rely on some judgement on where the front focus area starts and where the back focus ends. These are not hard lines because depth of field focus continuously improves to a focus point and then diminishes to the back end of the the dof.
The Reikan’s Focal System is taking digital measurements (I assume) and using statistics to determine where that peak focus is. I suppose that a weakness of this compared to the others is that we do not all want our peak focus point in the center of the DOF field. Some of us want a little front focus others a little back focus. This is visualized better on a visual system like lens align. But, you can get the same results by looking at the Reikan’s Focal System data and just picking an AF MA that will put the peak just forward or behind the optimum. But you won’t get the visual confidence that you CAN see in lens align.
Another issue with Reikan’s Focal System is the lack of a target to camera alignment system. Reikan’s Focal System does have a neat software system that verifies the target and makes sure that you have enough of the target in the view, that the center is under the cameras center focus sensor, and that the target is not rotated too far. But there is nothing that makes sure that the target plane is parallel to the camera sensor plane. As I discussed in earlier blog LensAlign Pro has a system that ensures these planes are aligned. I get around that by putting my target on a wall that is more or less perpendicular to the floor.
Another tip is the paper for the target. Reikan’s Focal System recommends a thick good quality paper. I ignored this at first and just used regular paper. Bad idea. I found that it is difficult to get regular paper to lay flat on a wall no matter how much you tape it down. In addition I think the higher quality of the paper allows for sharper edges on the target and this, I believe improves the test. The paper that I found works best is Office Depot’s Premium Brochure & Flyer Paper. Its 45 lb paper with a 96 brightness rating.
Its also important to have the target well lit. I started with just using the indirect light from my windows and the overhead room light. There were lots errors with added points needed. Next I tried a couple of small LED lights that I use for reading sheet music. FoCal instructions say to NOT use LED as it is a pulsing light. I checked it out on the internet and LED’s do pulse, some as slow as 60 hz. But they did work out fairly well with an occasional error. Recently I have been using a large bright (high kelvin) CFL that I use with my lightbox set up. FoCal also warns about this as it too pulses. But my research showed that the frequency of these lights are between 1200 and 45000 hz. All the tests that I have run with FoCal have been with a TCP spring light CLF (6500K), with a pulse frequency of 45K hz, work with this light. Note that I have found that at 45000 cycles per second that, from internet postings, that the phosphorescence in these CFL’s stay bright between pulsing that is that fast and therefore they are a constant light source. I think focal would like you to do this in direct sunlight, which I think is impractical, or will some other non pulsing light. I am guessing that there are studio lights that do that…. but I don’t have any so my set up will do.
Here is a video of the light discussion:
Positioning the target and camera are important as well. I measure the height to the center of the target. I then set up my camera on a tripod. I have a ball head with a level and make sure that the head is more or less pointing at the target and level.
I then put my camera on the head and adjust the camera height so that the center of the lens is the same as the center of the target. With that done I look into the viewfinder or the live view and move the tripod/camera left or right to put the center focus sensor on the target. If the height is not right I will adjust the height again. Sometimes I have to adjust the ball a tiny bit to make sure that the sensor is right in the middle of the target. But no major adjustments. And I deem that good enough. I am tempted to build a target like the lensalign but with the Reikan’s Focal System target. Note that I may have totally missed the technology associated with the Reikan’s Focal System and maybe target to camera sensor parellel-ness is not that necessary.
Here is how I do my final alignment of my camera to the target:
Finally I run the calibration. Now there are a lot of presets or preferences that you can set depending on whether you want a very thorough and complete cal or a more cursory one that just gets you in the ballbark. The camera settings need to be preset. Although the software will do a lot of this. The instructions that come with this system are long but very thorough and easy to understand.
When you start the software, with the USB connected it should recognize your camera as one of the cameras that you have registered to this software. You then need to run the target program to make sure the target is set up correctly. The software will provide a live view along with visual clues as to where you need to move the camera. The start the program. Get a cup of tea or coffee. Relax. But do it quickly because the calibration is relatively quick depending on your preferences. You can also watch the readings as the program goes through the MA selections.
About half way through you will see a colored bar (green) that will indicate an initial guess at the correct MA point. Then the program checks and validates the MA points near that point. Then you are done. The statistically optimum point is chosen and set. You can even download a report, with lots of pages, detailing the findings for that lens.
There are some other goodies on the software as well. It will tell you where the aperture sweet spot is on the lens. It will tell you if you have dust on your sensor and where it is. It will check to see how repeatable the camera lens combination is on AF.
I think this is just amazing. Here is video of my running a calibration on a Canon 5D Mk II with a 24-70mm f2.8 lens.
Finally, I did this cal with the 1.4 version of the software. It is PC only. They recently included both the Canon 5 D MK III and the new Nikon DSLR’s. I know that with the 5D Mk III that it will only run in semi-automatic mode. So everything is the same but I have to manually change the MA between each shot. Its not the best but I still will use it over the lens align because I trust the results. I think that Reikan is working on it. The Canon software necessary to run the auto was only recently release. And they are not sure if they will be able to make that camera automatic as of late May12.
The other cool thing is that there will be a MAC version coming out very soon. Its in beta release now. I do all my photo processing on the Mac side of my macbookpro so I would rather do the calibration on that side.
A final note. As cool as ALL of these lens microadjustment systems are, And again I think Reikan’s Focal System is the best, this does not guarantee an in focus shot. Could could be on a tripod looking at a stationary target. You could have the most rigorous Reikan or LensAlign calibration going for you. And the shot could still be a little out of focus with AF. Because AF is not 100% repeatable. The AF systems today are awfully good but not perfect yet. So I say do these calibrations and then take lots of shots…. One will be perfect!!
One more thing…. please do not look at the little bits of food on my glasses and lower lip…… Its embarrassing. I will know now to look in the mirror before my next video. But its too much work to do these things and I just figured…. what the hell.