Adjusting Focus With Datacolor Spyder LensCal - Digital Photography School

Adjusting Focus With Datacolor Spyder LensCal

I’ll warn you right up front; this post is not for everyone. Some cameras have the ability to make a fine tune adjustment to autofocus. For those with a camera model that allows for fine tune adjustments, checking focus accuracy can be important, especially when shooting macro images where pinpoint focus is more vital. For the average shooter, the millimeter adjustments might not be as vital.

First off, here is a list of camera models known to have the ability to make micro-adjustments. This list is by no means complete, so check your camera’s instruction manual to see if this ability is available to you:

  • Canon (50D, 7D, 5DMkII, 1DMkIII, 1DMkIV, 1DsMkIII, 1DIV)
  • Nikon (D7000, D300, D300s, D700, D3, D3s, D3x)
  • Sony (A850, A900)
  • Olympus (E-30, E-620)
  • Pentax (K20D, K7D)

I was sent a device from datacolor which aids in checking focus. You can certainly make your own device as the principle involved is simple: Focus camera on a known flat object and then measure front or back to where the camera is actually focusing. The time and know-how involved in making an accurate device would likely be comparable to the MSRP of $59USD for the datacolor LensCal.

Get a price for the Datacolor DC SLC100 SpyderLensCal Lens Calibration System on Amazon.

The Process

To check camera and lens autofocus (this test is best ran with each lens/camera combination you use) you will either need two tripods or a level surface. The LensCal comes with a tripod mount hole in it and it contains a bubble level.

Insure both the camera and LensCal are level, exactly perpendicular and at the same height. This is very important as being off to one side or the other, or pointing the camera slightly to the side, will cause an error in results. In my case, I used a table and bubble level. Turn off vibration reduction/image stabilization capabilities.

Lighting is important but not super critical, meaning a studio setup is not required. Make sure the target is light from in front. I chose a sunny day when the sun was slightly off of noon to give ample lighting.

datacolor notes the distance from lens to target should be around 5 to 10 times the focal length. The lens should also be zoomed all the way out, if it is a zoom lens. For instance, a 100mm lens should be 500mm-1000mm away. Some camera manufacturers might have other recommendations. The aperture of the lens should also be opened all the way (lowest number possible at that focal length) and it is best to use aperture priority mode. An open aperture will insure a shallow depth of field, making differences in focal points easier to spot. To help with viewing the image after shooting, I highly suggest using the lowest ISO you can achieve. There should be plenty of light available, so a low ISO won’t be a problem.

With autofocus turned on, choose a focus point at the middle of the target area. It’s important to not let the camera select a point from the ruler, which is why manual focus point selection is suggested. Now take a shot.

I suggest importing the photo into your computer for checking. Some people use the screen on their camera, which provides all the accuracy they are looking for, but I would not recommend its use. In the shot above, it appears my camera is back focusing; it is focusing too far to the rear. I note this by checking to see if the 0 is the sharpest point on the image. Here’s a 1:1 zoom of the above image (click for full size).

Now, I don’t have the best eyesight in the world, but I can see that the area behind 0 is more in focus than the area in front of 0. Is it huge? No, but it is noticeable. I selected a point about four steps back from 0 as what I thought was in focus. I then made the adjustment to my camera. Canon has an easy to understand symbol these days (it used to say Forward and Backward and confused some people). In this case, I adjust my focus backward by 4 millimeters, because it was back focusing.

I then reshot the target to check focus.

Is the change huge? Nope. And hopefully it won’t be for you too. At times I would use a 3:1 zoom in Lightroom to check, but at that zoom it becomes difficult to really tell. 1:1 works best.

Just to see how far out of whack things can be, here are two shots adjusted to -20 (pulling focus closer to the camera, creating more front focus) and +20 (just the opposite).

The biggest question I know many of you will ask; is the price worth the result? If you have multiple cameras and lens combinations, this device might serve you well (especially in a camera like the Canon 7D which allows for adjustments to be saved for each lens used). If you shoot macro, this device will also serve you well because at that range, millimeters often mater. Lastly, if you are a pro and tight focus matters to you, this device will help, especially if you rent lenses or upgrade camera bodies (it folds flat for easy storage).

For the average user, I would say the result might not justify the cost. In that case, an alternative method might be to shoot a flat, contrasting target and step through all 40 of the adjustments available (if your camera goes to -20 and +20). Then review in a computer and make your best guess which is most in focus. This is certainly more time consuming and requires a steady hand as you make about 120 presses of buttons on through your camera’s menus.

Check out the Datacolor DC SLC100 SpyderLensCal Lens Calibration System on Amazon.

Read more from our Tips & Tutorials category.

Peter West Carey is a world traveling photographer who now is spending a large amount of time going back through 6 years of travel photo and processing them like he should have to start with. He is also helping others learn about photography with the free series 31+ Days Of Photography Experiments which builds off of the 31+ Days To Better Photography series on his blog.

  • http://www.holidaycottageinbetwsycoed.co.uk Robert M Scott

    A programme can be downloaded for the Pentax K10D that allows access to the hidden focus adjustment feature. One thing missing from the article is that each adjustment is particular to that lens only and should be dialled out back to zero when changing lenses otherwise each adjustment is cumulative and you will lose track of where you are!

  • http://photos.rickscheibner.net Rick

    Sadly, the 60D is conspicuously absent from that list. This was going to be my next camera body until I discovered that little tidbit. My 50mm f/1.4 front focuses just a bit, and it’s quite noticeable at certain distances with anything wider than about f/2.

  • Karl Stevens

    I think you may have made a mistake here, because it looks like the lens was properly calibrated before you made the change to -4.

    the area behind 0 is more in focus than the area in front of 0

    If the lens is properly calibrated, this is exactly what you should see, isn’t it?

    Perhaps I’ve been misinformed, but I was under the impression that depth of field was not uniform front to back from the focal point – ie that the area behind the point of focus will be larger than the area in front of it – the amount I’ve heard is 2/3 back, and 1/3 in front. If this is true, wouldn’t it mean that if the “1″s are both the same, that your lens is miscalibrated?

  • http://matt.loper.org Matthew Loper

    Karl is exactly right: you have more depth of field behind, than in front of, the “perfect” focal point. Your lens may have been perfectly well calibrated to begin with. In my opinion, a better way to adjust focus is to use a fringe pattern. One example of how to do this is here.

  • http://www.kerstenbeck.com Erik Kerstenbeck

    Hi

    When I started I didnt even think of Lens Cal from Spyder, only colour Cal. Now I am a believer!

    Helps with critical focus like this shot of a Ford Hood ornament

    http://kerstenbeckphotoart.wordpress.com/2011/09/10/ford-reflections/

  • DeWitt Eaton

    I bought one of these shortly after they were released to (hopefully) correct a rear focusing issue I was having with my Nikon 85 f1.8 and my D700. Worked great! Happily recommended. Don’t think I’d use it on zoom lens’s though. Don’t want to get into issues of throwing off one length while correcting another.

  • http://www.focalmatter.com mike

    “If you shoot macro, this device will also serve you well because at that range, millimeters often matter.”

    If you’re shooting handheld macro, that is. If you’re shooting mounted macro, you generally wanna focus manually anyway.

  • http://www.focalmatter.com mike

    Also, while I’m a huge believer in the value of calibrating your lenses, I have trouble wrapping my head around paying $60 for something I can effectively build with a ruler and a protractor.

  • Odyn

    Or you can take a piece of paper, print this on it and do it for less than a dollar.
    http://www.alettaphoto.com/products/Front-%7B47%7D-Back-focusing-alignment–charts-for-any-DSLR..html

  • http://peterwestcarey.com Peter West Carey

    karl,
    You are mostly correct except that I mis-typed. The sharpest point was -4 and I moved that forward. The sharpest point is where focus is actually locked and that needed to be moved forward. My estimate of keeping the 1′s balanced is false and, in the end, not actually true when taking a close look at the images. The focus, to my eyes, is still more balanced to the rear, while the sharpest point is now 0. Thanks for helping me clear that up.

  • http://www.fuzzypig.com Fuzzypiggy

    A lot of time you can get calibrations done back at base by companies like Nikon and Canon, they have the top-notch kit available and sometimes they’ll even do it under warranty. I know this means losing the kit for a few days but when it comes back it’s one less thing to blame bad shots on I suppose!

  • lightimages

    Lens focus point adjustments (in video usually called back focus) are much more accurate with the lighting/shutter adjusted to get correct exposure at wide open aperture.

    Working with the smallest depth of field for the lens (widest aperture) shows the exact focus point clearly.

    Making these adjustments with a smaller aperture extends the sharp focus area, making it more difficult to see the point of exact focus.

  • Joe

    If you use Photoshop, use the Emboss filter on your picture. It makes it easier to see the sharp areas.

    I use the LensAlign system. Their website has a calculator for the different lens focal lengths & apertures & tells you how far the target should be from your lens & what the depth of field will be in mm, cm or inches etc

Some older comments

  • Joe

    September 17, 2011 08:34 am

    If you use Photoshop, use the Emboss filter on your picture. It makes it easier to see the sharp areas.

    I use the LensAlign system. Their website has a calculator for the different lens focal lengths & apertures & tells you how far the target should be from your lens & what the depth of field will be in mm, cm or inches etc

  • lightimages

    September 14, 2011 01:50 am

    Lens focus point adjustments (in video usually called back focus) are much more accurate with the lighting/shutter adjusted to get correct exposure at wide open aperture.

    Working with the smallest depth of field for the lens (widest aperture) shows the exact focus point clearly.

    Making these adjustments with a smaller aperture extends the sharp focus area, making it more difficult to see the point of exact focus.

  • Fuzzypiggy

    September 12, 2011 10:13 pm

    A lot of time you can get calibrations done back at base by companies like Nikon and Canon, they have the top-notch kit available and sometimes they'll even do it under warranty. I know this means losing the kit for a few days but when it comes back it's one less thing to blame bad shots on I suppose!

  • Peter West Carey

    September 12, 2011 07:42 am

    karl,
    You are mostly correct except that I mis-typed. The sharpest point was -4 and I moved that forward. The sharpest point is where focus is actually locked and that needed to be moved forward. My estimate of keeping the 1's balanced is false and, in the end, not actually true when taking a close look at the images. The focus, to my eyes, is still more balanced to the rear, while the sharpest point is now 0. Thanks for helping me clear that up.

  • Odyn

    September 12, 2011 06:55 am

    Or you can take a piece of paper, print this on it and do it for less than a dollar.
    http://www.alettaphoto.com/products/Front-%7B47%7D-Back-focusing-alignment--charts-for-any-DSLR..html

  • mike

    September 12, 2011 06:44 am

    Also, while I'm a huge believer in the value of calibrating your lenses, I have trouble wrapping my head around paying $60 for something I can effectively build with a ruler and a protractor.

  • mike

    September 12, 2011 06:43 am

    "If you shoot macro, this device will also serve you well because at that range, millimeters often matter."

    If you're shooting handheld macro, that is. If you're shooting mounted macro, you generally wanna focus manually anyway.

  • DeWitt Eaton

    September 12, 2011 06:21 am

    I bought one of these shortly after they were released to (hopefully) correct a rear focusing issue I was having with my Nikon 85 f1.8 and my D700. Worked great! Happily recommended. Don't think I'd use it on zoom lens's though. Don't want to get into issues of throwing off one length while correcting another.

  • Erik Kerstenbeck

    September 12, 2011 04:01 am

    Hi

    When I started I didnt even think of Lens Cal from Spyder, only colour Cal. Now I am a believer!

    Helps with critical focus like this shot of a Ford Hood ornament

    http://kerstenbeckphotoart.wordpress.com/2011/09/10/ford-reflections/

  • Matthew Loper

    September 12, 2011 03:56 am

    Karl is exactly right: you have more depth of field behind, than in front of, the "perfect" focal point. Your lens may have been perfectly well calibrated to begin with. In my opinion, a better way to adjust focus is to use a fringe pattern. One example of how to do this is here.

  • Karl Stevens

    September 12, 2011 02:41 am

    I think you may have made a mistake here, because it looks like the lens was properly calibrated before you made the change to -4.

    the area behind 0 is more in focus than the area in front of 0

    If the lens is properly calibrated, this is exactly what you should see, isn't it?

    Perhaps I've been misinformed, but I was under the impression that depth of field was not uniform front to back from the focal point - ie that the area behind the point of focus will be larger than the area in front of it - the amount I've heard is 2/3 back, and 1/3 in front. If this is true, wouldn't it mean that if the "1"s are both the same, that your lens is miscalibrated?

  • Rick

    September 12, 2011 01:47 am

    Sadly, the 60D is conspicuously absent from that list. This was going to be my next camera body until I discovered that little tidbit. My 50mm f/1.4 front focuses just a bit, and it's quite noticeable at certain distances with anything wider than about f/2.

  • Robert M Scott

    September 12, 2011 01:43 am

    A programme can be downloaded for the Pentax K10D that allows access to the hidden focus adjustment feature. One thing missing from the article is that each adjustment is particular to that lens only and should be dialled out back to zero when changing lenses otherwise each adjustment is cumulative and you will lose track of where you are!

Receive a FREE SAMPLE of our Portrait Photography Ebook

  • Guaranteed for 2 full months
  • Pay by PayPal or CreditCard
  • Instant Digital Download

Receive a FREE SAMPLE of our Portrait Photography Ebook

  • Guaranteed for 2 full months
  • Pay by PayPal or CreditCard
  • Instant Digital Download

Receive a FREE SAMPLE of our Portrait Photography Ebook

  • Guaranteed for 2 full months
  • Pay by PayPal or CreditCard
  • Instant Digital Download

Sign up to the free DPS PHOTOGRAPHY COURSE

  • Guaranteed for 2 full months
  • Pay by PayPal or CreditCard
  • Instant Digital Download

GET DAILY free tips, news and reviews via our RSS Feed

Sign up to the free

DPS PHOTOGRAPHY COURSE

  • Guaranteed for 2 full months
  • Pay by PayPal or CreditCard
  • Instant Digital Download

GET DAILY free tips, news and reviews via our RSS Feed

Sign up to the free

DPS PHOTOGRAPHY COURSE

  • Guaranteed for 2 full months
  • Pay by PayPal or CreditCard
  • Instant Digital Download
DPS NEWSLETTER
DPS NEWSLETTER
DPS NEWSLETTER

DPS offers a free weekly newsletter with: 
1. new photography tutorials and tips
2. latest photography assignments
3. photo competitions and prizes

Enter your email below to subscribe.
Email:
 
 
Get DAILY free tips, news and reviews via our RSS feed