Autofocus Performance: Technique and Technology

I received an email recently that thanked me for the AF Micro-adjustment info, but also asked about how to test the AF function in general on the 50D. They already select the AF point manually (a key first step), but some images are in focus while others are not; also – if they shoot a sequence, there are also issues with some images being in focus and others not.  I responded via email, but figured this would make a great post.

A few things to consider:

What AF mode are you using?
You are shooting w/ a set focus point – that is key, but also ensure you are in AI Servo mode. One Shot will almost never work w/ any sort of movement. (Canon terminology, but Nikon has similar modes)

Is it out of focus? Or is it motion blur from either the camera motion or the movement of the subject?
Are you running a fast enough shutter speed? The rule of thumb for handheld for *stationary* objects is is 1/focal length… so if you are in w/ a 400 mm lens, you should be shooting handheld at 1/400th or better if the thing you are shooting is standing still… then if you add motion into the mix – you need to have great panning and a steady hand, and IS, and a faster shutter speed.

What is the color/pattern of where the focus point is?
The af systems are all based on contrast and the ability to find enough contrast to check for focus (the main reason that low light AF sucks). If your subject is consistent in color, or the light isn't great, that may give the AF system fits…

Which AF point are you using?
Keep in mind that (with the 50D – but this applies to other cameras as well) the center point has the best sensitivity – All work at f5.6 but only the center point has additional sensitivity for lenses of f 2.8 or better…  Consider using the center point, keep zoomed out just a bit from how you would crop in camera, shoot the pic, and then crop during post processing to get the final picture you want.

How fast is the thing you are trying to shoot moving, and how far away are you?
You can be shooting something fast that is far away but coming at you, or you can be shooting something slow but is close, and you can have the same problems – relative speed.  Consider this… Someone moves 10 feet closer to you in 1 second as you try to keep them in focus…  If they are 100 yards away, not a problem, you're looking at only 3.33% of the distance between you two lost… If they start 40 feet away – they've moved 25% of the way towards you… but are still moving the same speed.

Is it moving towards you or side to side?
Towards you is the AF system, side to side is your panning technique.

If towards you, is it moving towards you linearly? 
I'm not positive, but I think most of the AF routines are geared towards linear movement… I track a lot of cyclists at a velodrome.  Depending on where I am and they are on the cycling track, they may be speeding up or slowing down relative to my position at different rates, even though they are moving at a constant speed.  Then couple that with the varying distance to the subject and relative amount of distance closed per second… and the brain can lock up thinking about it all…

Which lens is key too!
How fast (bright, low f-stop) is the lens, how fast the AF motor in the lens is, etc.

The difficult thing in all of this is finding ways to test that are consistent… so that you know it is your technique or the camera, or the situation that is the issue.  Finding players in the same uniforms, in the same light, at the same distance, and so on…

I found that a lot of practice was what really helped increase the number of "keepers" I had out of any photo shoot that involved sports photography.  Practice, practice, and then practice some more. The whole time trying to focus (no puns intended) on one or two of the above items during each session. If you try to include them all early, you'll just drive yourself batty.

Camera companies all (yes, both Canon and Nikon) put their better systems in their pricier bodies. Not too surprisingly, I found much better AF performance when I started using a used 1D Mark IIn (considered by some to still have the best AF performance out there).  The additional focus points, the better AF system, coupled with a great fast lens like the 70-200 f/2.8 L IS, make for even better performance – but mainly after all the other things are sound to begin with. I've loaned my 1D to some friends who still have lousy keeper rates w/ it.

At the risk of repeating myself – practice… practice… practice.

When you are shooting a sequence by holding the shutter down, keep in mind that all of the above is still very much (if not more so) in play; especially if the subject is close. If there is little contrast to the uniform or color where the AF point is targeting, the AF system may not recognize that the subject is even moving. You get the idea…

Oh – practice… practice… practice!

Thanks for reading!

Canon Crop Comparison: FF vs 1.3x vs 1.6x – Bokeh

Who hasn't wondered what the hubbub is all about. All this "crop factor" talk. Full frame, 1.3x, and 1.6x (well – for the Canon-ites out there).  I think we all understand how it effects the reach of our lenses, but how does it effect the bokeh of our images?

A Quick Re-wind…

For those who may not know the first part of that, it is pretty straight forward.  The crop factor, multiplied times the focal length of your lens, yields an "effective" focal length number, or "35mm film equivalent" number.  A full frame sensor – sized the same as a negative – has a no crop factor, or really a value of one. For Canon, this would be the 5D, and the "s" flavors of the 1D series – the 1Ds, 1Ds Mark II, and the 1Ds Mark III.  Most of the entry level (and again – I'm typing "Canon" speak here) and mid level cameras are 1.6x, (Digital Rebel, 400D, 20D, 30D, 40D, 50D, etc) while the Canon 1D (non "s") cameras toe the line at 1.3x (the 1D, 1D Mark II, and 1D Mark III).

So – in practical numbers (and an easy one at that) if you put a 100-400mm zoom on each of the different crop factor cameras, set it as wide as it could go (at the 100mm position), you would get photos out of them that appeared to be taken at 100mm (the full frame), 130mm (the 1.3x), and 160mm (the 1.6).  This can be a bonus if you are looking for extra reach out of your lens, but can be a detriment if you are looking to get wider angle shots.

Back to the Point of Today's Post…

Okay – the sharp end of today is what about those middle zones… what really is the difference? Does the crop factor make any difference to the photos that would be framed the same in all three ratios?

Let's say three people, one with each crop factor type, see the same subject and want to photograph it. We'll also say that all three people stand the same distance away from that subject and frame their shots the same way through their viewfinders. Okay – and – miraculously enough, all three are using the same lens and decide upon the same settings for f-stop and shutter speed. How will their pictures be different?

Sure – we need to throw out the differences in the sensor's sensitivities, color saturation, etc… those really are not a factor of the crop factor itself, just a part of the construction of the sensor elements and image processing software and firmware.

How the Test was Done…

I have a 1D Mark II N and a 50D, so I had the 1.3x and 1.6x covered; luckily a friend – Kevin – just picked up a 5D. Voila – gotta love a plethora of bodies to test with. Now that the gear was covered, it was pretty easy to configure a test that would minimize differences and allow for valid comparisons.

A few of my vintage cameras soon were on a table with a magazine propped up against the wall to serve as a more defined thing to get out of focus in the background. I mounted my 70-200 f/2.8 L IS to my tripod, and switched off the IS.  To get the same net image, the effective focal lengths had to be the same. For the FF and 1.6, the math was easy, shoot the 1.6 at 100mm shown on the lens, and shoot the FF at 160mm. Some quick math (160/1.3) yielded 123mm for the 1.3x.  We ended up shooting w/ the 50D first, so we metered with it and chose the exposure of 1/10th at f/2.8 (we chose the f stop to minimize the depth of field). Other tidbits – all the cameras were set to "neutral" picture style; RAW;  I shot gray cards to set custom white balance for all three cameras; all were set for mirror lockup and a remote trigger (wired) was used.

After shooting, the images were brought into Lightroom, I did boost the vibrance on the shots from the 50D as the colors looked very different from the other two bodies (more on that later - as in another post). They were then exported as 800px wide images, 70% quality, sharpen for screen (for the "full image" pictures posted here); and as 100% quality, scaled to match the smallest (the 1D) image dimension so that when cropped, they would all be the same size, no sharpening.

The Results…

The three photos below (click to enlarge) are the three "as they filled the viewfinder" images. The 1.6x (50D) at the top; the 1.3x (1D Mark II N) in the middle, and the full frame (5D) at the bottom.

CropC-1

CropC-2

CropC-3  

Okay – to sum it up – there is a very noticeable difference between the three photos. Now the distance for these was about 7 feet from the camera to the cameras, and another 8 inches or so to the magazine. The two areas that seem to illustrate the bokeh difference for me are the forearm of the rider and the lettering of Velo News.

On the forearm, the word GARMIN is sorta readable in the 50D (1.6x crop), is a bit blurrier on 1D (1.3x crop) and is darn near un-readable on the 5D (full frame).  In the lettering of the N, you can see how much the orange color expands and blurs as the crop factor gets smaller.

Now, some might think – wow – what if I don't want that much bokeh… I should avoid full frame… Nope – just don't shoot at f/2.8.  You can add depth of field by going to f/4 or f/5.6.

The key thing here is, if you are looking for MORE bokeh, moving to a full frame sensor camera body will do the trick. It isn't just buzz… it is very noticeable.

Thanks for reading!

Fullest Full Moon – A quick post…

Tonight was the largest the full moon will appear to us this year – the full moon closest to the Earth in its orbit, that is.  There was some haze on the horizon and some low thin clouds in the way as well, but here are a few shots from tonight… Started w/ just the EF 100-400 f/4.5-5.6L IS; then added the 2x TC; then added the 1.4x as well for the last shot.  The second to last shot was with my EF-S 17-55 f/2.8 IS – a self portrait of sorts. As always – click to enlarge. Thanks for reading!

VeryFullMoon-1 VeryFullMoon-2 VeryFullMoon-3 VeryFullMoon-4 VeryFullMoon-5
VeryFullMoon-6 VeryFullMoon-7

 

Vosonic VP8860 Multimedia Viewer adds Canon 50D RAW Support

Not sure if you've considered a multimedia viewer for your bag, but with the 15.1 MP images comin' out of my Canon 50D – long days of shooting can burn through CF cards pretty quickly. There are numerous options out there, Epson probably the most mainstream, but I went with the Vosonic. Quite a few factors led to that decision, but I'll save that for another post. Short version – I'm a huge fan of the VP8860.

Today they finally released a firmware update for the VP8860 that supports RAW files from:

  • Canon EOS 50D
  • Canon EOS 5D Mark II
  • Sony Alpha 200
  • Sony Alpha 900

The firmware update can be found here on the VP8860 Firmware download page and you can read aobut the viewer on the VP8860 Product Page

Thanks for reading!

Hands On: Really Right Stuff L-Plate for the Canon 50D Review – BGE2-L50

Well – if you've visited before, you know I've been curious about the new offering from Really Right Stuff (RRS) in the L-bracket department – specifically, one for the Canon EOS 50D. It got one ordered last week and it arrived today – right in the midst of me swamped trying to head out of town for a short notice “day job” meeting.  I did take a break long enough to pull the CNC machined piece of aluminum glory out of its plastic zip-loc bags (yes plural – parts in bags in other bags – can't have anything get scratched en route!); mount it to the 50D (which and made it up to the office for just such an occasion) including the poorly explained strap lug thing. The problem was I had to get back to work, hop in the car and drive to Austin.

After finishing up the prep for the meeting, I was able to take a closer look and get some photos taken.

Suffice to say (go figure) that this L-plate is well designed and the machining and finish are impressive. After getting the RRS L-plate for my 40D and getting great service from it, there was no doubt I was going to go with RRS for my 50D.  I could go on about the stuff that is carried over from the 40D, but a summary will do – the same great curved base to prevent spinning on the bottom of the camera; a nice balance between material needed for a stiff bracket and the need to save weight; curved corners that fit the hand comfortably when the camera is not mounted on a tripod; and so on… oh – and let's not forget the "captive" screws that won't fall out when you remove the plate from the camera.

Okay – so what will you prattle on about Will? What's new – of course!

Overall Shape:
RRS-5 They've re-worked the bend in the bracket – it is now wider and looks like it will do a better job of protecting the battery grip from those accidental bumps. If you are like me, you don't take your L-plate off the camera once it is mounted… For me it adds to the comfort/size of the grip when in the vertical position.  They've also worked on squaring off the opening for the cable connections, and even my ham-fingers can easily get in there and open the rubber covers. I can't tell you how glad I am that I've been able to move my 40D plate back over to my 40D… it was a bit odd to continue to use my work-around for the 40D plate w/ the 50D.

That Strap Thing:
RRS-1 Okay – it's the only thing that I felt that RRS didn't do a good job of showing off on their product page here, nor in their "no-copy" photo only setup instruction RRS-8 sheet. Now – don't get me wrong - an L-Plate is a chunk of aluminum that you bolt (literally) onto your camera… how hard could it be?  I'm not expecting a nice 36 page manual with a table of contents and an index or anything, but the pics were all a longer shots with no real detail or info about the function of the "thing".  On the RRS site, the new BGE2-L50 page just says "Strap mount boss at top of plate helps stabilize the camera with battery grip."

Insert tab A into slot B…
RRS-2 RRS-3 RRS-4 

Essentially RRS uses the screw on bit to anchor the end of the L-plate to the body by using the metal tab that is normally used to attach the strap to the camera.  When you mount the plate to the camera, it snugs up and you pretty much can't leave the strap attached to the camera directly… Then you take the spare screw and the "thing", thread the screw into the threaded end of the slot on the "thing" and then screw it into the end of the L-plate. There is a little tab on the bottom of the "thing" that will drop nicely into the slot in the camera strap tab on the side of the camera…  Just attach your strap to the loop-o-aluminum and voila! You're now ready to roll.

You can get Shifty too!
RRS-6 As we all know who have them, the Canon remote trigger plug is far from short… it is a few millimeters taller than the L-plate is thick. This is not a problem when you are shooting in landscape mode, but when looking to mount the camera in portrait RRS-7 mode (you know – the reason you got the L-plate in the first place – grin) you can't do it… well – not without shifting the plate on the camera. This is where the new version of the plate shines, in my opinion. The screw openings in both the base and in the "thing" are slotted, meaning that you can loosen the two screws, slide the camera, and then re-tighten the screws.  With the tab on the "thing" holding onto the slot of the camera strap tab, it does a great job of stabilizing the camera when the plate is not snug up to the side of the camera.

Overall – I like the look and configuration of this new L-plate, and I'm looking forward to using it soon.

Thanks for reading!

Canon EOS 50D – ISO 100 Photos

Okay – so I've posted a few low light shots from my velodrome work in my 1370 post, but I'd not had the opportunity to shoot a daytime event to that point. So here are some shots from a Fall series race a few weeks ago. All shots were taken at ISO 100 with the Canon EOS 50D using the 100-400 f/4.5-5.6 L lens. I've left full EXIF on the enlarged photos, tho I'm not sure if Typepad will keep that data in place after upload. You can click to enlarge the images.

Enjoy and thanks for reading!

SPS-Fall3-050-3582 SPS-Fall3-051-3597  SPS-Fall3-073-3772 SPS-Fall3-075-3790  SPS-Fall3-080-3938 

Really Right Stuff L-Plate for Canon 50D with Battery Grip

Okay – they had told me they were working on one, then the w/out battery grip was posted on-line, then "coming soon – accepting pre-orders" was next for the version with the battery grip.

BGE2-L50 I just took a quick look today and voila! The BGE2-L50 is now available with some images posted.

At first glance it looks like it has been worth the wait. A nice wide opening for the cables, the ability to get the covers open with the l-plate in place, and the plate looks like it will provide good protection for the corners of the BG, perhaps better than the 40D version did. It also appears that there is now an extension of the plate to allow for the camera strap to connect to the plate itself. The photos don't show the detail of this strap tab that well, but it appears that it may be removable – it looks like there is a screw that may allow you to remove the tab if you don't want it – or to easily remove the camera from the plate if you don't want to un-do the strap from the bracket tab itself.

Yup – one is order and should be here soon (I think Monday) – I'll post a review w/ images and my thoughts then.

Thanks for reading!

Canon 50D HDMI Output – Useful?

Okay – so one of the often referred to but rarely detailed new features on the 50D is the HDMI output port. It lives in the same strip of output ports on the side of the camera as the USB and "old fashioned" video out connections.

Today on the drive home from work, I popped into a local electronics store and bought an HDMI-A to HDMI-C cable. I only sprung for the 6' cable as I'm not sure what I'd use if for (in practice) and how often I'd make use of it at that.  I've seen posts where you can pick a cable up for $7 – 10 bucks… I dropped a few more than that, but well short of the $50 that Monster Cable is looking to get from you.  I know there are folks who swear by the better cables, but – again – since I'm testing, figured I'd get a fair idea for my $15 outlay…

Slide Show:

Okay – I think the most obvious use for this would be the slide show of images at the end of a day out and about. Quite a few hotels are starting to put flat panel displays in their rooms, and who knows – if you are over at the relatives for Thanksgiving, why not wow the crowd with a slide show of shots from the days activities.

A quick insertion of the cable into the back of the set, plug the other end into the camera, power it on, hit the "menu" button to get to the slide show, and voila! The new 50D menu is now show in 56" DLP glory… No – I don't think they really push the menu at 1080, but then again – I'm not sure at what resolution they push the output of the images either. A search of the "Instruction Manual" and one with with Google – pretty much came up with nothing. Other than saying "output for high definition screens" – there isn't much detail as to what the output resolution is, if it only renders to the high resolution for the slideshow, or does plain old image playback render in high def? Perhaps the yet to be published 50D White Paper from Canon will shed some light on these questions.

So other than finding that the HDMI-C connector wasn't introduced until HDMI 1.3, and that HDMI is a bidirectional standard, allowing the video device to understand what the capabilities of the display device are – thus sending the proper signal (480p, 720p, 1080i, 1080p) for the best image… I still couldn't find what the output capabilities were of the camera itself.

I had a CF card in the camera that had about 15 shots from a walk with my dog along the canals near my house, so I navigated the billboard sized menu (remember, I've only a 6' cable connected to the back of my set… LOL) till I had fired up the slide show.

Issue number one… Auto rotate of images setting…
When I shoot, I have the camera auto rotate the images only on the computer. That way – when I shoot and preview a landscape shot, it will display the way I just shot theimage, not "vertically" in the LCD when you look at the back of the camera normally… It allows me to get a better sense of the shot before I start to zoom (if needed) and I don't need to rotate the camera out of the attitude that I had just used for taking the last shot.

So – as I watched the slide show, the images that had been shot portrait were rotated by 90 degrees on the screen… Easy enough. Stop playback, navigate the billboard to be "Auto rotate on camera and screen"… Back to the slide show and voila!… I was cookin' w/ grease.

Problem number two… I'd shot all portrait…
Yeah – whoda thunk, but all the shots I'd taken had been portrait… so while the shots looked nice and all, they were not filling the DLP with glorious color… Okay – I can out- wit this camera, right?

I soon went to my computer, brought up the high res .jpgs I used to post to my web site for purchase by my customers, and dropped them onto a CF card. A few minutes later, CF card in the 50D – and the "no images" ignominy stared me in the face…

You guessed it (okay – or maybe not – I ran into this when I tried showing the same .jpg on the 40D and 50D in some earlier tests), I'd dropped the images onto a blank formatted CF card. Seems the camera wants to only read images from the DCIM\100Canon (or similar) directory. Again – no problem, I thought – copy a few images (only three or four to ensure I'd got it right), pop the CF in the camera, and it mocks me yet again… "Cannot Play Back Image" it says… with an artful clip-art yellow question mark on a gray faded background just below the message. Ever the mule (read as stubborn), I roll the thumb wheel to the next pic and find the same, but the third time was the charm… the third image showed just fine.

Curious…

A Sesame Street flash back of "which one of these things is not like the others" ran through my head and I quickly realized (well – guessed) that I had cropped the other two images, and perhaps the camera, not finding one of its "native" resolution files, was unable to display it.  I finished copying the images over, deleted the ones that didn't display, and found that I had about 30 images left to flip through.

Okay – back over to the big-screen, re-connect the cable, and voila! My images on the DLP w/ grand and glorious color!

I'll admit the vertical images were a bit disappointing, just not really filling the screen, but still looking pretty good. It was the landscape shots that took the day… Unlike the NTSC output, the HDMI was indeed giving the full 3×2 ratio of the image with just small black bars to the left and right of the image. Nothing like the bars left right above and below when using the NTSC output.

Live View:

The other HDMI tethered output thought that I've seen has been for "live view" usage. Yes – it does give you quite a large screen, but I'm not sure how practical this really is.  If you're shooting in your living room and you do have a big screen monitor, and for some reason, the nice 50D LCD won't do the trick – sure – run w/ the big screen… LOL… But I think USB connected to a laptop will be just a bit more practical configuration – especially given the AF adjustment you can do from the EOS Utility.

HDMI-1 It did let me get a curiously interesting repeating image photo… Which, after the fact, seems a bit curious that it actually turned out. The image shows the magnification area of the live view screen cascading back as the image of the image of the image shows on the television. I snapped the shutter, and before the image I had captured showed, I figured I'd wasted a shutter actuation. I figured that the live view output would shut off before the shutter fired; but I was surprised to see the image was captured.

Non-Slide Show Image Playback:

As I was playing around with the camera with the output, I went to image playback and started reviewing images. This was actually pretty cool - for some reason cooler than the slide show I'd seen earlier… the ability to see the images on the screen, to zoom in and see detail on the screen, was pretty neat. I guess I could see where I'd not have my laptop at a client site, they may not have a raw image conversion tool, but w/ a high def projector or big-screen tv in a conference room. I'd be able to pull the cable out of my bag and rather than several folks crowding around the camera as I chimped through images, I'd be able to share the images with a larger group. 

Conclusion:

Okay – so is the HDMI output really of use? Well – in a pinch, yes… but for most practical purposes, no… But I'll throw in a bit of a caveat here… It would *not* be of practical use for how *I* shoot.

I shoot a LOT of images when I'm out…

When I was shooting in college for the paper, yearbook and campus quarterly, they beat it into our skulls to always load 36 exposures into the cannisters from the bulk loader. The event was expensive, film was cheap. Shoot portrait and landscape, frame a bunch of different ways. This just became my shooting routine, to the point where, when I got back from vacation, no one wanted to look at my photos when I picked them up from the lab. Everyone learned to wait till I'd culled my photos for the ones I liked.  I do the same (and even more so) now with digital being so cheap.  Long story short – I'd bore the snot out of anyone looking over my shoulder at Thanksgiving, or back in the hotel room at the end of a day of sightseeing. LOL

If you shoot with great restraint, and you do like to share pics w/ the family the same day – sure – this will work great for you.

Most other situations, a laptop with a USB cable will serve me much better than the HDMI cable. Live view with a USB cable, especially when you remote shoot and store your images directly on the laptop. Presentations and review of images with a client would work better than using an HDMI cable with the camera. Also, more of my clients would have projector that took the output from a laptop than one that has HDMI input.  Also - I have more tools to cull through photos on the laptop than just showing images from the camera.

As a final note – I pretty much burned through a battery doing my live view and other HDMI output tests. So while Live View is already a power hog, this takes Live View and other card/display intensive tasks to new battery draining heights…or lows…

If you've other thoughts for the use of the HDMI (well – other than video – do you really want the zoom square in your movie? I don't think so…) please leave me a comment below.

Thanks for reading!

Canon 50D Shutter Actuations Counter (and Canon 40D too!)

Just a quick post before knocking off for the evening.

Saw a post today on canonrumors.com that had a link to a site that has a free piece of software that can read the (until now) Canon Support territory of how many actuations a shutter has. The idea is pretty basic – it uses the EOS Utility drivers (you put this .exe file in the same directory as the EOS Utility) to access the information from the camera. You plug in the camera to your computer with a USB cable, turn it on, close the EOS Utility if it starts, then start this application. Click the "Get Count" button and voila!.

This program accesses information from the Digic III processor (or the Digic IV) so the app will work on the 40D, 50D, and the 5D Mark II, but not on the 30D, or 350D,400D, etc…

It was interesting to see that my 40D has 27,010 actuations, but how accurate is it? Well, my 50D shows 3,961 – which shows 4 more than the highest image number. This results from some "remote shooting from PC" which counts as a shutter actuation, but since the file is saved directly to the computer, so the compact flash card count doesn't get increased. So I'd say that the 27k actuations reading on my 40D is pretty accurate.

This is only for the PC, not for the Mac, but you can read all the details here.

Thanks for reading!