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This is the assembled Lens Align Mark II. Thanks to Michael Tapes for the image.
It’s simple. While the images made with most rigs are sharp, in many cases, they will be that much sharper with more fine detail once a given camera body/lens or camera body/TC/lens combination has been properly micro-adjusted. While some of my rigs are spot on, others have needed front- or back-focusing corrections as high as +/- 12 units.
The Lens Align Mk II; Micro-adjusting Magic!
Ever since the introduction of digital camera bodies that feature micro-adjustments for individual lenses, folks–including me–have been searching for a quick, easy way to make those micro-adjustments. When I was working on the 7D and the Mark IV User’s Guides, I worked hard on developing a make-it-yourself cardboard rig that was a big improvement on the original version. But in reality, it did not offer the needed precision. And in addition to the extremely low cost, the rig took up lots of space–heck, it was huge, and using it was tedious work.
I had heard about Lens Align for some time, but a quick web check revealed that it was expensive. And performing the calibrations seemed to require somewhat of an extraordinary effort…. But, Michael Tapes, the designer/creator/inventor of Lens Align–with the introduction of the Lens Align MkII about 2 years ago–drastically changed the playing field. But having to tether your rig to a laptop still made things a bit on the cumbersome side. Working with both Peter Kes and Robert O’Toole I have developed a neat way to micro-adjust your lenses without being tethered to a laptop or other computer. As with many of my writing projects this one has taken far too long, in fact, the Non-tethered Micro-adjusting Tutorial below comes in second only to the creation of The Art of Bird Photography II; that one took four years but at 916 pages with more than 900 images I had a good excuse.
The Lens Align MkII offers an inexpensive, accurate and repeatable methodology that allows photographers to test for potential front/back focus issues. The MkII maintains the high quality standards of the original LensAlign Pro and uses the same patent pending True Parallel Alignment™ (TPA™) Sighting System that is an exclusive feature of all genuine LensAlign products. TPA allows the user to establish exact parallel alignment between the camera’s sensor-plane and the focus target of LensAlign quickly and easily. The huge failure of all other AF micro-adjustment products and procedures (including my incredibly crude efforts in the two most recent User’s Guide Updates) is their inability to ensure true parallel alignment. TPA is, however, an absolute requirement for accurate and repeatable AF testing and and for making accurate and repeatable micro-adjustments. The Lens Align MkII costs only a fraction of the original Lens Align Pro and–with the slightly longer ruler, and the new ruler patterns, it performs even better. You can order yours right now for only $79.95 plus shipping: ~$6/US or ~$13/INT via Priority Mail. Please be aware that the shipping fees may vary a bit depending on your location or when you order through the BAA On-Line Store. International shipping charges will also vary by country depending on additional fees for customs, VAT, duties, or fees depending on their laws, rules or policies. You can send us a Paypal, call Jim at 863-692-0906, or purchase through the BAA On-Line store here.
Lens Align Non-Tethered Testing & Micro-adjusting Tutorial
Non-tethered testing is fast, easy, and much more convenient than tethered testing. Below I will teach you how to do it and how to make a few images to confirm your results.
All you need is a relatively level and open spot for you to set up your lens and the LA Mark II on tripods. I far prefer to work outdoors so that I have lots of light and contrast. I generally try to do my micro-adjusting (MA-ing) on cloudy bright days. Even when working with shorter focal length lenses it is best to work outside. With non-tethered testing it is not necessary to install EOS Utility from the CD that came in the box with the camera. And Nikon folks do not need to purchase Nikon Camera Control Pro 2 Software Full Version for Nikon DSLR Cameras or Breeze Systems’ NKRemote as they did for tethered MA-ing.
Here is exactly how I do non-tethered MA-ing with my Canon gear. I set up a tripod with the big lens that I will be testing with the camera body attached. I make sure that only the central sensor active and that no surrounding points are enabled. I work in Av mode at the wide open aperture. I make sure that the Live View/Movie function is set to Stills. Make sure to set the AF Mode to Quick Mode. I like to have the focus confirmation beep on. I set the ISO high enough to give me a decent shutter speed to ensure that my final confirmation images are sharp. I use rear focus and believe that that is the best option for MA-ing. And I set the Drive Mode to Single Frame Advance.
I keep a spare Wimberley P-5 plate on the base plate of the Lens Align MKII. Next I grab any old tripod–a light one is fine, and screw on my Giotto’s tiny ballhead (the Giottos MH 1302-655) which is ideal for the chore. (Any ballhead will do.) Note: the unit comes with a 1/4 20 threaded hole that requires a mounting plate with a 1/4 20 bolt. Having the LA MII on a small ballhead makes the alignment process (described below) a snap.
Now I take the tripod with the Lens Align MKII atop it and walk off the prescribed distance. It is recommended that all lenses including telephoto lenses be tested at distances of at least 25 times the focal length of the lens. That works out to 8.2 feet per 100mm. I usually work at about 20 times the focal length; that works out to a bit more than 6.5 feet per 100mm. For a 500mm lens that’s about 32.5 feet. You can either estimate the distance by walking it off or use a carpenter’s rule. A good rule of thumb without calculating or measuring anything is to set up so that the corners of the central AF sensor are just touching the edges of the main focusing circle as seen through the viewfinder.
Camera Settings Review
For your calibration efforts it is–as above–imperative to check and make sure that you camera is set up properly for testing:
- Central Sensor AF point (selected manually) with no surrounding points enabled.
- Av mode at the wide open aperture
- Live View/Movie function set to Stills
- The Live View AF Mode needs to be set to Quick Mode
- The (focusing) Beep is On.
- The ISO is set high enough to give you a decent shutter speed to ensure that the final confirmation images (if you choose to make them) are sharp
- Rear button focus is set.
- Drive Mode should be set to Single Frame Advance
Walk off or estimate the distance and set down the small tripod with the LA MII on top. Loosen the ballhead just a bit while still maintaining enough tension to prevent it from flopping. Then point the Lens Align roughly at the lens. Then look through the TPA’s Rear Sighting Port’s Main Target on the back of the unit, center the lens barrel in the center of the viewing port, and tighten the ball. This part is easy.
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This is the view from the back of the Lens Align Mark II. Thanks to Michael Tapes for the image.
Next I return to the camera set up and aim the lens so that the central AF sensor is on the center of the large focusing target on the left side of the Lens Align Mark II unit as shown in the image below.. Getting the central sensor to rest precisely on the center of the target once you tighten the tripod head may require several attempts and you will never get it done perfectly. Close is good enough. I will teach you how to deal with this situation below.
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This image shows the central AF sensor just touching the edges of the main circular target. This configuration gives you about 20 times the focal length for any lens regardless of focal length.
Attaining True Parallel Alignment
The next step is to align the camera and lens so that the camera (actually the imaging sensor) is perfectly parallel to the test target. As it turns out, this is–thanks to the brilliance of Michael Tapes and his ingenious design, sometimes fairly easy to do. But at times it can be frustrating. The very best case is to work with a partner who is capable of making minute adjustments to the aim of the LA MII as per your instructions. That way you do not have to walk back and forth until you are happy with your aim and the position of the edge of the red circle inside the hole in the center of the target.
With your tripod head tightened and the central AF sensor on the circular main target, focus, activate Live View, and magnify the image to 10X. As long as you have taken care and centered the lens in the Main Target from behind the device you should see at least parts of the red target circle in the hole in the center of the focusing target. If the circle made by the edge of the red circle is–as shown in the image below–perfectly centered in the hole in the target then you are ready to continue.
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This Michael Tapes screen capture shows the red ring centered in the hole in the center of the focusing target. If this is what you see at 10X, then your rig is perfectly square to the test target; you have attained True Parallel Alignment. Note: you will only see a thin bit of red–I am guess that this image was enhanced for educational purposes. 🙂
If the red circle is well off to one side or too high or too low, you or your assistant will need to re-aim the LA MII, re-focus, re-activate Live View, magnify to 10X, and see how you did. Trial and error is required when attempting to re-aim the LA MII. Sometimes you may get so frustrated that you simply start over by re-aiming from behind through the Rear Sighting Port’s Main Target. In any case, you do not need to have it as perfect as it is in the image above. If you can see at least part of the red circle all the way around you can proceed with confidence.
You are now ready to determine if your rig–the lens and the camera–are front or back focused. Activate Live View. Turn the manual focusing ring on the lens counter-clockwise to de-focus the image just a bit. You may have to “bend your rig” a bit by shifting the lens so that the AF sensor is precisely on the main target. This is easy to do even with the image de-focused a bit. Then you focus. Now magnify to 5X. Use the joystick to shift the view to your right so that you can see both the main target on the left and the ruler on the right. At 5X the ruler should be just about filling the horizontal frame from top to bottom.
Now look carefully at the pairs or numbers above and below the zero mark. If all the 4s, 8s, and 12s look equally sharp and relatively in focus and the sharpness falls off equally as you look at the pairs of 16s and 20s and the pairs of 28s, 32s, and 36 look equally blurry then the single image that you created is neither front- nor back-focused.
Here’s the rub: in order to determine that your result was not a lucky (or unlucky) fluke, we recommend that you take a look at at least ten Live View rounds of focusing, five slightly de-focused by turning the manual focus ring counter-clockwise, and five slightly de-focused by turning it clockwise. Important note: after viewing in Live View at 5X be sure to go back to the full screen view each and every time before focusing again so that you can be sure–even though you have de-focused the image a bit—that the active AF sensor, the central sensor, is squarely on the main focusing target. If 8 of the 10 show neither front- nor back focus then you are good to go. You can be confident that your rig is neither front- or back-focused.
Just to be clear on everything above. You are not making any images. You are not tethered to a laptop. You are simply focusing multiple times while in Live View and checking the results on the large LCD screen on the back of the camera as detailed above.
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Note first that what you see above is roughly what you will see on the rear LCD at 5X magnification. In this image that the 4s, 8s, and 12s are all in relatively sharp and focus falls off equally above and below them. Note that when you view the screen at 5X on the rear LCD that it will be relatively easy to determine front of back focus. This image was actually created with the 500II/5D Mark III with a micro-adjustment of -2 dialed in to correct for slight back-focus.
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The image above represents what you would see on the rear LCD if your camera/lens combination were severely back-focused. To correct such severe back focus you would need to dial in an adjustment of approximately -15 units; you want to move the focus towards the camera. Remember, however, that you need to focus about 10 different times after de-focusing the lens manually in different directions. Never make a micro-adjustment based on a single Live View view or test image.
You can see additional examples of front- and back-focusing in the original tutorial here.
To learn to perform the actual micro-adjustment please consult your camera body manual or a BAA camera User’s Guide. Once you have entered the needed micro-adjustment for a given camera body/lens combination you may wish to create a series of three to five test images being sure to de-focus manually after each image. It is not a bad idea to set your Picture Style to Monochrome to make the images easier to see clearly once you download them and view them on the computer to double-check your non-tethered micro-adjustments.
Specific instructions for doing the actual micro-adjustment on the EOS-1D MIV can be found in the original tutorial here.
Important note: you must make individual micro-adjustments for each lens/camera combination and for each lens/teleconverter/camera combination (with individual MAs for the 1.4X and the 2X TC. If you own and use two 1.4X TCs for example, understand that the camera will not be able to differentiate between them. I mark my two 1.4X TCs with a black Sharpie so that I can tell them apart.
If you are confused at all by this tutorial feel free to leave questions or comments below. Do note that I will be without internet access from 10/17 through 11/11. Peter Kes and Michael Tapes, however, will likely be able to help.