focus point

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I began to discuss the autofocus modes of various dSLR cameras in previous posts including Taking Control of Your Canon Autofocus System and Taking Advantage of the Autofocus Systems of the Nikon D5100 and the Nikon D7000

In this post I wish to go into more detail about one of the reasons it is important to take control of your autofocus system, namely not allowing the locations of the AF Points in your viewfinder to dictate your final composition.

As I mentioned in previous autofocus posts, one of the essential steps in taking a successful photo is controlling where the camera focuses.  If you allow the camera to auto focus by choosing its own focus point(s), it typically focuses on the closest object.  This may or may not be what you want to focus on, so you should select where the camera focuses using the Auto Focus Points.  For example, you often want to focus on a subject’s eyes, but if you allow the camera to choose the autofocus point itself, it may select another part of the face, or somewhere else on the body, or even a raised hand that is nearer to the camera than the face to focus most sharply on.

In addition, there are reasons to use the outer focus points and not just focusing with the center AF point and then recomposing.  First, if you are taking several shots of the same subject and framing, you will not have to re-focus with the center point and recompose between each shot.  And by controlling exactly where you focus, you then have greater, more precise control over the use of dramatic depth of field.  Also, if you use the center point and recompose, you have swept the camera in an arc to recompose, and are thus always focusing at a distance behind the subject.  This may not be as noticeable when the subject is further away, but for a close subject – especially when using shallow depth of field – the difference is critical.

One of the additional critical reasons to take control of your autofocus system is so that you don’t let the location of the AF Points dictate your composition. What happens when the subject you want to focus on is not located exactly under one of the AF Points? Even with 9 or 19 or more AF Points to choose from, they will not always be located exactly at or near where you need them to be.  Recomposing or re-framing your shot is often necessary so that you can capture exactly the image you wish to and not one dictated by the locations of the AF Points as you see them in the viewfinder.

Canon 7D 5D mark II 60D T3i 600D autofocus system AF point choose select set setting
Figure 1 – The desired framing and composition of the shot I wish to take, yet no AF Point, including the selected lower right point (the larger point shown in red here) is located exactly at the woman’s head where I wish to focus. (Canon 7D viewfinder shown)

Canon 7D 5D mark II 60D T3i 600D autofocus system AF point choose select set setting
Figure 2 – Image is temporarily framed to place the selected AF Point over the woman’s head, Shutter Button is pressed half-way and held to lock focus at that distance, image is recomposed to the desired framing of previous Figure 1, and Shutter Button is fully pressed to capture the image.

Figure 1 shows the desired framing and composition of the shot I want to take, but the woman is not located under an AF Point. This composition is desired for me because it captures the entire window along with some space around it, as well as some space in front of the woman for her to “walk into” – but not an excessive amount of space. So I manually select the lower right AF Point (using Single-Point AF Mode), temporarily frame the image to place the selected AF Point over her face or head, press and hold the Shutter Button half-way to lock focus at that distance (Figure 2), and see the Focus Confirmation Light illuminate in the viewfinder. I then recompose back to the final framing I want (Figure 1) and press the Shutter Button fully to take the image. Even though the subject is moving, I do not need the sophisticated tracking of AI Servo (Canon) or Continuous Servo (Nikon) Focus Mode to keep her in focus. I can quickly lock focus using One Shot (Canon) or Single Servo (Nikon) Focus Mode, recompose, and take the image without the camera-to-subject focus distance changing significantly.

With the example images above (Figures 1, 2), focusing on the wall would not have been tragic because the distance between the subject and the background is small, and if a medium or narrow aperture such as f/8 or f/16 is used both the wall and the subject may be in acceptable focus. If the background was further away, and/ or a wide aperture such as f/2.8 was used – especially with a telephoto lens, and if the image was enlarged, you would clearly see that the camera focused on the wall and not the woman. Not to mention the fact that the wall is a somewhat consistent area of color and the AF system may have difficulty properly focusing on it. So it is best not to take shortcuts such as focusing on the wall and hoping the subject will also be in focus, because in many other situations you will not have this option. It is best to take the photo properly and to learn and practice the habit of working in the more rigorous manner if you want all your photos to be sharp.

If you would like to learn more about the autofocus systems of your Canon or Nikon dSLR camera, as well as learn to use the other features of your camera including metering modes, Aperture and Shutter priority modes, all the menus and Custom Function settings, and more, have a look at my Full Stop e-book camera guides. In addition to explaining the features and settings, the guides clearly explain when and why to use them in order to capture the images you desire.

Take control of your camera and the images you create!

Learn more about the e-books by clicking on their titles or on the banner below:
Canon 7D Experience
Canon T3i Experience
Your World 60D
T2i Experience.

Nikon D7000 Experience
Nikon D5100 Experience.

full stop dslr photo photography camera manual guide for dummies canon nikon

For those with other cameras, check out my Ten Steps to Better dSLR Photography which also discusses taking advantage of any dSLR camera’s autofocus system.

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I recently returned from a trip to Guatemala, where I was taking photos for an NGO that works with children, literacy, and education. It gave me the perfect opportunity to try out a bunch of new equipment and really put it to the test in the field.


San Miguel Duenas, Guatemala – Canon 7D, 70-200mm f/4L IS lens at 78mm, 1600 ISO, 1/100, f/5.6

Jump to the Custom Function section

First and foremost, it was the first time I really had the opportunity to use the Canon 7D body (I discuss the additional gear in this related post). The camera performed wonderfully in many ways, however, I did have autofocus related problems – namely a serious front focus issue. With both wide angle and telephoto L-series lenses, the camera was consistently focusing several inches or more in front of the subjects. I played around briefly with the AF Microadjustments, with the intention of taking a closer look at the situation when I returned home.  (Body was later exchanged for another that focuses properly.)

I had another, odd and unexpected complaint in the field, and that is with the high speed shooting modes. One has the choice of 3fps or 8fps, yet I needed something more like 5fps! I’ve included some images throughout the post that are straight from the camera (I merely converted from RAW to JPEG). Anyway, on to the review and instructions for many of the camera’s settings, and how and when to use them in real world situations. And at the end there is some info about video tutorials available for downloading and watching.

If any of the digital photography terms you come across in this post are unfamiliar, be sure to refer to this great glossary for assistance.

Design – The camera is extremely comfortable to hold and use, especially due to the size, shape, and material of the grip, and it felt to be designed perfectly for my hands. It is nicely weighted with both a 16-35 f/2.8L II and a 70-200 f/4, and carries well with an R-Strap attached to the camera body (the 70-200 f/4 doesn’t come with a collar). Due to its similar design and button placement as previous Canon models, it was easy to get used to changing various settings on the fly – everything from ISO right up on top to Flash Control in the menus. There are a few settings that I quickly fell into, but that I would like to experiment with a little more with before I settle permanently into. Here are a few notes, in no particular order of importance:

Av Mode – I set the camera to Av mode for 99% of the time, as that is how I typically work (because I always want to control the depth of field). About the only time I took it out was when I was experimenting in an HDR type situation where I was in Manual and bracketing, trying to properly expose both a dark colonnade I was under and the cathedral in bright sunlight beyond. I haven’t yet worked on combining the exposures, but here is a nice shot that came from that situation:


Antigua, Guatemala – Canon 7D, 16-35 f/2.8L lens at 16mm, 1600 ISO, 1/500, f/16

(edit – I added the camera and lens information to these images.  Please note that the camera settings used for these various images may not necessarily be the “best” or “ideal” settings to use in the specific situations, but camera settings are always the result of changing situations and lighting, coming from another scene, going back and forth between action and still subjects, adapting, experimenting, and sometime just plain not paying attention!)

ISO – I had high hopes for Auto ISO, thinking I would finally be given the freedom to stop worrying where I left it set, but I quickly found that in Av, I didn’t like the slow shutter speeds that were resulting when I selected the aperture and the camera selected the ISO. So I ended up never using it. I would like to experiment with it some more, and figure out if there is something I can do to keep the shutter speeds in a better range. It is wonderful to have the versatility to change ISO on the fly, but one often gets caught up in shooting, and forgets to change it to an appropriate setting, and thus sometimes the shutter speed isn’t the most ideal. So, I just have to stay in the habit of paying attention to where all three settings are as I go from indoor to out or change lenses, etc. This is aided by these settings being visible in the 7D viewfinder.

High Speed Continuous Shooting – many people marvel at the 7D’s ability to shoot 8fps in High Speed Continuous Mode. However, for my purposes on this trip, that proved far too excessive. I often shoot a burst of photos when someone or something is in motion and I want to capture the peak of action or a flattering pose, or when a gesture or facial expression might change rapidly. Unfortunately, 8fps results in a lot of unwanted files, and as I will soon address, these files are HUGE and rapidly fill up a hard drive. But sadly, the Low Speed Continuous drive setting is only 3fps, which is too slow to capture the rapid changes in a scene. The 3fps speed was one of the main drawbacks of my previous body, and a major reason for upgrading. What I need is something in between, maybe 5fps! Perhaps Canon or someone will tweek the firmware to allow this…


San Miguel Duenas, GuatemalaCanon 7D, 16-35 f/2.8L lens at 35mm, 800 ISO, 1/500, f/3.5

Custom Functions – In order for you to get the most out of the 7D, and to set it to function best how you work, you need to dig into the Custom Functions. One of the settings I use is customizing My Menu, and then having My Menu always appear first when I hit the Menu button. (My Menu Settings / Display from My Menu=enable) I played around with different items on My Menu, but have settled for now on the ones that I use most often or that I may quickly need and want to access without digging into the menus. They are:

Flash Control
– you can quickly adjust all the settings for the built in flash, external flash, wireless flash. You can even control all the setting of the 580EX II remotely – when it is not attached to your camera. Very cool.
Exposure Compensation/ AEB – exposure compensation is easy to change at any time with the big dial, so this shortcut is for using when I want to bracket (AEB).
Review Time – I found that I was often shooting away without chimping (looking at the LCD), so I often just turn off the LCD review altogether. Other times, however, I want to review.
ISO Expansion – I haven’t used this yet, but I wanted it handy in case I want to use the high ISO. I typically have this turned off because I didn’t want the camera to default to High ISO during any situations. But considering I wasn’t using Auto ISO, this all seems unnecessary, and now that I realize this, I will have to replace this with something else on the menu! I never went above 1600 ISO, which I did have to use sometimes in very dark classroom settings along with the flash. Upon quick review of those images, the lack of noise in these files is really good.
Format – this is to format the memory card in preparation for use the next day. Always reformat the card, never simply erase them or use the Erase All option if your camera had that (the 7D does not). However, after formatting, turn the dial to select another menu item so that next time you hit Menu, Format isn’t still selected and you quickly make a grave mistake of pressing it.
Highlight Tone Priority (II-3) – this is a great setting to use in a high key situation, or with a bright subject or scene. It helps to retain detail in the highlights so they don’t get blown out, such as a white wedding dress, or a snow or beach scene. I never did use it, but I keep it in this menu to remind me it is there for the day when I do need it!


Chichicastenango, Guatemala – Canon 7D, 70-200mm f/4L IS lens at 155mm, 200 ISO, 1/80, f/4

Other important Custom Function Settings

(please note, this post was initially written to explain how I used these settings in a specific travel situation.  I go into more detail about each of the Custom Function settings, with clear explanations of what they are and when and why to use them, in my e-book Canon 7D Experience, which is discussed below.)

Safety Shift (I-6) – I sometimes enable this setting. It allows the camera to shift the shutter speed or aperture automatically, without your expressed permission, in order to get the shot. This is great for situations where the light suddenly and dramatically changes, such as at a concert.  However if you are carefully choosing your settings, or working with a flash, you will want to disable this so that the camera isn’t overriding your careful settings.

AI Servo Tracking Sensitivity (III-1) – This dictates how quickly focus tracking switches to another subject when it momentarily loses the initial subject, such as when another subject passes in front of it. You can choose to have it stay focused on the initial subject (Slow), or focus quickly on a new subject that moves in front of your initial subject (Fast). Typically I want to stay focused on my selected subject, and ignore someone or something that momentarily passes between us. If you want to quickly focus on different subjects at different distances, put it on fast.

AI Servo 1st/2nd (III-2) – Is your priority focusing on the subject, tracking the subject, firing off rapid shots? Look at the manual to see which situation works best for how you shoot.Personally I think 0 or 1, with the autofocus (AF) Priority, is best. (The camera makes sure it focuses first before taking the shot. It may cost you a microsecond of time however.) Regarding tracking vs. drive, I keep it at 0. Setting 0 continues to prioritize focusing possibly at the expense of speed, while setting 1 will prioritize the speed of subsequent shutter releases at the expense of focus.

AI Servo AF Tracking Method (III-3) – This works with autofocus modes where more than one AF point is active. The names of the choices are a little confusing but what they do is Setting 0 will focus on a closer subject that enters into your view, not necessarily in front of your subject. while setting 1 will remain focused on the initial subject. I keep mine on 1, since I want to stay focused on my initial subject.


San Juan del Obisbo, GuatemalaCanon 7D, 70-200mm f/4L IS lens at 200mm, 100 ISO, 1/1000, f/4

AF Focus Mode (III-6) – I enabled all the AF modes in the Custom Functions – by default, several of them are not available to you unless you change that setting. I started out using Single Point, but sometimes changed to Spot for more precision. The cost of using Spot is that it may not focus as quickly or as well when hand held or with a moving subject, and is generally not necessary unless you are trying to focus on a very small, precise area, such as through a fence to a subject beyond.  I occasionally used AF Point Expansion when photographing rapidly moving children. I don’t know how other photographers work (according to a Canon rep who gave a 7D presentation at B+H, there are big name professionals who still just focus with the center point and recompose), but I always choose the focus point I want manually, using the Multi-Controller button. This takes a little longer, now that I am dealing with 19 focus points, but that enables me to quickly get the composition I want, makes sure the camera focuses on what I want it to, and to get subsequent shots without too much reframing. There is an important menu setting so that you can use the Multi-Controller directly to change the AF point without having to press the AF thumb button first – I believe it is on the screen where you can customize all the camera’s buttons. Oh, and I changed the custom settings so that all the focus points always show, and that they light up upon achieving focus, even in bright sunlight (which they would not do if you had this setting on Auto or Disable). That way I always know when it has focused.  And I set Custom Function III-7 to stop focus point selection when I reach the edge and not loop around to the other side. I’m also thrilled that the 7D has a grid display that you can turn on in the viewfinder, which helps me keep my horizons and compositions straight. The viewfinder looks pretty busy, filled up with AF points and the grid, but when you are shooting away and focusing on your subject, you don’t even notice they are there.

Single Point Focus vs. Spot Focus Size – This controls the size of the area being looked at for focusing purposes on the 7D.  With Single Point AF Area Mode, the camera is actually looking at a cross shape area (all focus points are cross type, center point is dual diagonal as well at certain apertures) that extends about 2x as big as the actual square you see in the viewfinder. With Spot AF Area Mode, the size of the cross is about the size of the square you see, I think perhaps slightly larger.  Now you might think that using Spot AF will be more accurate all the time and sounds like a great idea and will get you sharper pictures, but this is not necessarily the case.  Since Spot AF is so precise, and since autofocus works by looking for an area of contrast, Spot AF may not focus as well or as quickly in many general situations (because it may be looking at such a precise area that is all one color or  tone).

Spot AF is for when you need a really precise “focus beam” to pinpoint, for example a bird in a tree, and not the branches and leaves surrounding it and all around it, which may be closer to you and the camera.  Or if, say, you are shooting through a chain link fence and you want the camera to focus on the animal beyond and not on the fence.  If you were to use Spot AF all the time, you would have to continue to act in a slower and more precise manner, so that you ensure you are focusing on an area of contrast or a nice line.  For example, if you capture a shot of a person, you want to focus on the eye typically.  If you do this quickly with Single Point AF, you can aim at the general area of the eye and you will likely include it in the area being looked at by the camera.  However if you grab a quick shot with Spot AF, you may  be a little off and the camera is looking at an area of cheek to focus on, which will be difficult since there isn’t much contrast there.

Orientation Linked AF Point – This setting allows you to choose your favorite AF points, and when you are hold the camera horizontally or vertically, those points are automatically selected. However, it is very complicated to set, so much so that is would seem Canon doesn’t even understand it. The Canon rep did not fully explain it properly at the B+H presentation, the instructions in the manual do not work, and after 3 different instructions by email from Canon, I may finally have the correct way. I still have to try their latest directions. (note- nope, latest instructions still don’t work properly) **12/17/2009** AHA!! Here it is, finally explained in its entirety.

I also changed the button/ dial function settings so that in Manual mode, the big dial controls shutter speed and the top dial controls aperture. The default is the opposite. I changed this because I almost always shoot in Av mode, where the top dial controls aperture, so when I switch to Manual mode, I want that to remain the same.

Additional edit – August 2011:
I have written a popular e-book user’s guide for the Canon 7D
called Canon 7D Experience. It not only explains all of the features, functions, and controls of this powerful, sophisticated, and highly customizable camera, but also when and why to use them in your photography – including EVERY Menu item and Custom Function setting, with explanations and recommended settings for real-life use.  You can learn more about the guide, preview it, and purchase it here.

 

AF Microadjustments – This is a setting on the 7D which enables you to tweak the auto-focusing to your different lenses. A site about AF micro adjustments that look to be helpful is below:

http://www.northlight-images.co.uk/article_pages/cameras/1ds3_af_micoadjustment.html#Anchor-Canon-49575

Here is a micro-adjustment focus test chart you can use.

Viewfinder – The viewfinder on the 7D is big and bright and wonderful. It is nearly 100% view of the image you will capture. The aperture and shutter speed info is of course displayed below, along with the current ISO setting, which one should get in the habit of glancing at often. See the AF Focus Mode category above for more info on what you can view in the viewfinder to assist with focusing and composition.

Picture Style – I had this on Standard, since I shoot in RAW and intend to post-process, however, I would like to do a comparison of the styles to see which one best matches my visual preferences – although the Picture Styles will only affect JPEGs and, it is important to know, the image you see on your rear LCD screen when shooting RAW.


Jalapa, GuatemalaCanon 7D, 16-35 f/2.8L lens at 35mm, 800 ISO, 1/2000, f/8

File Size – I shot RAW for almost the entire trip, and quickly discovered that these files are HUGE. The files range from about 21MB to around 31MB each. I used SanDisk Extreme III 16GB cards, which worked great, and one card often lasted much of the day. I have no good reason for using SanDisk over Lexar, other than the fact that the Lexar people haven’t approached me about sponsorship… :) The Extreme III cards have been replaced by the new Extreme and Extreme Pro cards, and are thus the old ones are much cheaper at the moment, especially with current rebates. At 30MB/s, they were fast enough for the types of shooting and short bursts I was doing. However, downloading them to my computer and external HD were pretty slow using the SanDisk ImageMate CF card reader. Eventually I’m going to have to spring for a card reader that goes right into the PC slot. I used Adobe Bridge to simultaneously save the day’s files to 2 external hard drives. The 160GB Iomega Ego filled up before the trip was over, but fortunately I also had a Lacie 500GB. I am dreading the number of external hard drives I am going to have to buy for travel and for home storage, but once you go RAW, it’s hard to go back to shooting just JPEG. I’m going to have to look into the Drobo system that many rave about.

Battery Life – The battery life of the 7D is excellent. When you get new batteries, first charge them all the way. Do not recharge until they are completely drained. Do this one or two cycles. I know they say you no longer have to do this, but some claim that seasoning the batteries like this will maximize their charge life. Anyway, one battery lasted well into 2 days of shooting, maybe longer, I didn’t keep track. They just keep going, even with heavy use, chimping (LCD reviewing), frequent use of an external Speedlite flash, and use of image stabilization (IS) on the 70-200 lens. I carried 3 batteries, but probably could have gotten away with 2. The spring-loaded battery door that pops right open for quick battery changes is a nice touch.


Antigua, Guatemala – Canon 7D, 70-200mm f/4L IS lens at 78mm, 100 ISO, 1/250, f/4

Automatic Sensor Cleaning – Like most good dSLRs these days, the 7D automatically cleans the sensor at start up and shut down. Since the dust that is shaken off is collected on a tiny sticky strip at the base of the sensor, it seems to me that you should hold the camera straight as this happens. I’m not sure if this is actually true, but I think I read in the manual that it even says to place the camera flat on a table as you use this, so I have gotten in the habit of holding it straight and still as I turn it off and on. Yeah! No more having to clean the sensor manually with a Rocket Blower!

Video – I did not have a chance to even experiment with the HD video on the 7D yet…so much to learn, so little time…

The next post will review all the other gear I used on the trip – the camera backpack, R-strap, accessories, etc. – and perhaps some of the other lessons learned. Read it here.

Purchasing: If you plan to buy the Canon 7D or any other camera or equipment from Amazon.com, I would appreciate it if you use my referral link by clicking on the text or logo below. Your price will be the same, and they will give me a little something for referring you, which will help support this blog. Thanks!


See and buy the Canon 7D on Amazon

And due to popular request, if you are in the UK, here is my referral link to Amazon UK.

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Jalapa, GuatemalaCanon 7D, 70-200mm f/4L IS lens at 200mm, 200 ISO, 1/1600, f/4

Again, be sure to check out my e-book user’s guide for the Canon 7D called Canon 7D Experience. It not only explains all the features, functions, and controls of this powerful, sophisticated, and highly customizable camera, but also when and why to use them in your photography. You can learn more about the guide, preview it, and purchase it here.

I’ve run across a nice set of video tutorials (link below) for using the Canon 7D. You can watch them online, or even download them to your camera for viewing. The one on AF Custom Fuctions is especially helpful at clarifying those setting. Be sure to look around on the Canon Digital Learning Center to find all kinds of other cool stuff about using your camera plus useful tips and instructions from pros who use them.

link to Canon 7D Video Tutorials

The distinctive voice you hear in the 7D tutorial videos is Canon guru Rudy Winston, and the photo samples are his images as well. If you are in NYC, you can often find him leading workshops and presentations at places like B+H and Adorama. I went to a wonderfully informative introduction to the 7D that he gave a B+H a month or 2 ago, and these videos are pretty much the same presentation.

Here is additional information from Canon Europe about custom functions of the 7D:

http://cpn.canon-europe.com/content/education/technical/custom_functions_eos_1d_mark_iv_and_eos_7d.do