{"id":7049,"date":"2011-10-06T19:50:06","date_gmt":"2011-10-06T23:50:06","guid":{"rendered":"http:\/\/www.birdsasart-blog.com\/?p=7049"},"modified":"2011-10-10T15:55:03","modified_gmt":"2011-10-10T19:55:03","slug":"beanbag-sharpness-issues","status":"publish","type":"post","link":"https:\/\/www.birdsasart-blog.com\/baa\/2011\/10\/06\/beanbag-sharpness-issues\/","title":{"rendered":"Beanbag Sharpness Issues"},"content":{"rendered":"\n\n\n
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This image was created down by the lake near my home at Indian Lake Estates, FL with the Canon 800mm f\/5.6L IS lens<\/a> and the EOS-1D Mark IV<\/a>. ISO 400. Evaluative metering +2\/3 stop: 1\/1000 sec. at f\/8 set manually. <\/p>\n

The 800 was supported by a BLUBB<\/a> resting on the raised window of my SUV. BLUBB<\/a> stands for Big Lens Ultimate BeanBag. I custom-designed this large beanbag for use with super-telephoto lenses. The non-slip concave top of this great beanbag makes it easy to keep your lens perfectly still. Nothing out there compares with the BLUBB<\/a>, especially the cheap knock-offs that cost half the price. A peek at the Bubble Level in the hot shoe ensured that the lens was square to the world. <\/p>\n

Lens micro-adjustment: -4. Central sensor AI Servo\/Rear Focus AF and recompose…. <\/p>\n

For a greater appreciation of the image, click on the photo. Then click on the enlarged version to close it. <\/p>\n<\/td>\n<\/tr>\n<\/table>\n

Beanbag Sharpness Issues<\/h3>\n

Most folks with long lenses realize the benefits of using their cars as a blind in a variety of situations. If you are not in that group, see “Using Your Car as a Blind” on pages 120-121 of the original “The Art of Bird Photography<\/a>.” In addition, if you search for the word “vehicle” in ABP II<\/a> (916 pages on CD only) you will turn up 58 occurrences; many of those relate to tips for using your car as an effective and movable blind. <\/p>\n

This afternoon I received the following e-mail from Assaf Gavra:<\/p>\n

Hi, I am using a homemade beanbag made from two pillow cases and filled with 5kgs of beans. I have seen that many of your tack sharp images have been created with a big lens and the 1.4X III tele-converter. So I lost my fear of using it on my 500mm f\/4L IS \ud83d\ude42 but some of the images (most of them in fact) are not in focus. Considering that I have this top equipment I really don’t know what to do…. Can you help? Assaf<\/p>\n

Needing more info I wrote back asking “Have you ever made one sharp image with the 500 and the 1.4X TC??<\/p>\n

He wrote back and attached two nice images asking if they were sharp. Each was quite sharp. I wrote him back as follows:<\/p>\n

Assaf, Yes, they are razor sharp. That means that the lens and camera and TC are fine. That’s the good news. The bad news is that I now know why many of the images that you make are unsharp: operator error. That means you. I will address the question of beanbag work and image sharpness in tonight’s blog post. In the meantime I would recommend that you get yourself a copy of ABP II<\/a> and study the section on advanced sharpness techniques so that you can learn to create sharp images while working on a tripod. There is also lots of info on using your car as a blind in ABP II<\/a>.<\/p>\n

Assaf’s e-mail got me thinking: there are some complex issues involved when using a big lens from the vehicle and working on a big beanbag, issues that I had never written about specifically until now. Consider the BreezeBrowser<\/a> screen capture below and we will get started. <\/p>\n\n\n\n
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I would advise that you read the following material very carefully if you wish to learn to make a higher percentage of sharp images when photographing from your vehicle. In the screen capture above you will note that none of the AF squares are lit up red. That indicates that AF (in this case, AI Servo AF) was not active at the moment of exposure. I focused on the bird’s eye (using rear focus and the central sensor). Then I released the rear focus button effectively locking or setting sharp focus on the Turkey Vulture’s eye. If you have no idea what I am talking about, it means that that you missed the rear focus tutorial; you can find it here<\/a>. If you know what I am talking about but do not use rear focus, then for this section assume that you are using One-Shot AF and recompose. (That would be Single Servo and recompose with Nikon.) <\/p>\n

OK, here we go. Whether you use rear focus and recompose as I did to create the image above or One-Shot (or Single Servo) and recompose as I used to do, you will have arrived at the critical moment. Either way you have set focus. But whatever system and method you are using, focus is never actually locked. It is set. If you turn the manual focusing ring at this point you will change the focus. What most folks do not realize is that when they move the lens up or down or left or right to recompose there is a huge danger of inadvertently turning the manual focusing ring. If you are aware of this possibility and take care not to rotate the lens at all the problem can easily be avoided. So, after focus is set, take great care to ensure that the focusing ring does not turn even a hair else you will throw off accurate focus. <\/p>\n

Conclusion: if you are using rear focus and recompose or One-Shot (or Single Servo and recompose) with relatively fast shutter speeds and many of your images are not sharply focused it is likely that you are accidentally turning the manual focusing ring after focusing. <\/p>\n\n\n\n
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In the BreezeBrowser<\/a> screen capture above, note that that the AF sensor in the upper left corner of the array was not only selected but was active at the moment of exposure; you know that because it is illuminated in red. That indicates that I was holding down the rear focus button (with AI Servo engaged) at the moment of exposure. If I had been using the shutter button to focus it would have meant that I was in AI Servo AF (C or Continuous with Nikon) and that focus was active at the moment of exposure. In either case, accurate focus would be pretty much guaranteed for several reasons: <\/p>\n

1-The system was focusing when the image was created.
\n2-Accidentally turning the manual focusing ring (with Canon for sure…) would not have affected accurate focusing as electronic manual focusing is disabled when AI Servo is active.
\n3-The chance of inadvertently turning the manual focusing ring would be virtually eliminated as you would be happy with the composition created with the active focusing sensor right on the bird’s eye, face, or neck; there would be no need to recompose. <\/p>\n\n\n\n
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This Black Vulture image was also created down by the lake near my home at Indian Lake Estates, FL with the Canon 800mm f\/5.6L IS lens<\/a> and the EOS-1D Mark IV<\/a>. ISO 400. Evaluative metering +1 stop: 1\/800 sec. at f\/8 in Av mode. <\/p>\n

As above, the big lens was supported by a BLUBB<\/a> resting on the raised window of my SUV. BLUBB<\/a> stands for Big Lens Ultimate BeanBag. I custom designed this large beanbag for use with super-telephoto lenses. Nothing out there compares with the BLUBB<\/a>, especially the cheap knock-offs that cost half the price. A peek at the Bubble Level in the hot shoe ensured that the lens was square to the world. <\/p>\n

Lens micro-adjustment: -4. Upper left corner AI Servo\/Rear Focus AF active at the moment of exposure. <\/p>\n

For a greater appreciation of the image, click on the photo. Then click on the enlarged version to close it. <\/p>\n<\/td>\n<\/tr>\n<\/table>\n

Conclusion: if you are able to select a sensor that falls on the subject’s eye, face, or neck and you work with AI Servo AF (or Continuous with Nikon) active at the moment of exposure, you will be virtually assured of an accurately focused image. <\/p>\n

Additional Tips<\/h3>\n

1: When using a Bubble Level (I always do) be sure to point the lens at the subject first. Now set the camera body square to the world and then focus. If you focus first and then square your rig to the world you will turn the focusing ring and screw up the accurate focus that you had set. <\/p>\n

2: All else being equal, images made with lens\/camera and lens\/TC\/camera combinations that have been micro-adjusted with the Lens Align Mark II<\/a> will always be sharper than those those made with rigs that have not been focus calibrated. <\/p>\n

3-If time permits, shut off your vehicle’s engine before making a photograph. While this seems obvious, there are times when it is best to take an image or two with the motor running. If you think you know when it is proper to do this, please leave a comment. Hint: there are two qualifications. Only one is obvious :).<\/p>\n

4- Leave your pillows on your bed; the BLUBB<\/a> is the bomb and was designed to help you make sharp images with big lenses when working from a vehicle. We ship them all over the world every week. <\/p>\n

Which Image Do You Like Best?
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Take a moment to leave a comment and let us know which image you like best, the Turkey Vulture image or the Black Vulture image. And be sure to let us know why. <\/p>\n

Earn Free Contest Entries and Support both the Bulletins and the Blog by making all your B & H purchases here<\/a>.<\/strong><\/h2>\n

More and more folks are earning multiple contest entries with their B & H purchases. See here<\/a> for details on that. Eleven great categories, 34 winning and honored images, and prize pools<\/a> valued in excess of $20,000. Click here<\/a> to visit the competition home page. <\/p>\n

Shopper’s Guide<\/strong><\/h2>\n

Below is a list of the gear used to create the images in today’s blog post. Thanks a stack to all who have used the Shopper’s Guide links to purchase their gear as a thank you for all the free information that we bring you on the Blog and in the Bulletins. Before you purchase anything be sure to check out the advice in our Shopper’s Guide<\/a>. <\/p>\n

Canon 800mm f\/5.L IS lens.<\/a> Right now this is my all time favorite super-telephoto lens.
\nCanon EOS-1D Mark IV professional digital camera body.<\/a> My two Mark IVs are my workhorse digital camera bodies. <\/p>\n

And from the BAA On-line Store:<\/strong><\/h2>\n

LensCoats<\/a>. I have a LensCoat on each of my big lenses to protect them from nicks and thus increase their re-sales value. All my big lens LensCoat stuff is in Hardwood Snow pattern.
\nLegCoat Tripod Leg Covers.<\/a> I have four tripods active and each has a Hardwood Snow LegCoat on it to help prevent further damage to my tender shoulders \ud83d\ude42
\nGitzo GT3530LS Tripod.<\/a> This one will last you a lifetime.
\nMongoose M3.6 Tripod Head.<\/a> Right now this is the best tripod head around for use with lenses that weigh less than 9 pounds. For heavier lenses, check out the Wimberley V2 head<\/a>.
\nCR-80 Replacement Foot for Canon 800<\/a>. When using the 800 on a Mongoose as I do, replacing the lens foot with this accessory lets the lens sit like a dog whether pointed up or down and prevents wind-blown spinning of your lens on breezy days by centering the lens directly over the tripod.
\n Double Bubble Level.<\/a> You will find one in my camera’s hot shoe whenever I am not using flash.
\nBe sure to check out our camera body User’s Guides here<\/a>.
\nThe Lens Align Mark II.<\/a> I use the Lens Align Mark II pretty much religiously to micro-adjust all of my gear an average of once a month and always before a major trip. Enjoy our free comprehensive tutorial here.<\/a>
\nCanon EOS-1D Mark IV User’s Guide<\/a>. Learn to use your Mark IV the way that I use mine. Also available for the 7D and the Mark III here<\/a>. <\/p>\n","protected":false},"excerpt":{"rendered":"

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This image was created down by the lake near my home at Indian Lake Estates, FL with the Canon 800mm f\/5.6L IS lens and the EOS-1D Mark IV. ISO 400. Evaluative metering +2\/3 stop: 1\/1000 sec. at f\/8 set manually. <\/p>\n

The 800 was supported by a BLUBB resting on the raised window […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[90,28,5,25,24,12,14,17,29],"tags":[],"class_list":["post-7049","post","type-post","status-publish","format-standard","hentry","category-90","category-800mm-f5-6","category-educational","category-indian-lake-estates","category-mkiv","category-photo-equipment","category-photography-tips","category-product-info-and-tutorials","category-tips","odd"],"_links":{"self":[{"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/posts\/7049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/comments?post=7049"}],"version-history":[{"count":0,"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/posts\/7049\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/media?parent=7049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/categories?post=7049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.birdsasart-blog.com\/baa\/wp-json\/wp\/v2\/tags?post=7049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}