Tips & Techniques - Back Button Focusing

Every once in a while you find out a little tip that makes a big difference to camera handling.

Back button focusing was one for me about four years ago now.

On the Canon cameras before the the 1Dmk3 and 40D you could make the * button on the rear panel your Auto focus button by selecting the appropriate Custom Function in the sub menu system.

From the 1Dmk3 and 40D onwards, Canon fitted an AF-ON button next to the * that would do the same job.

However, being used to the position of the * button I use another tool in the sub menu to switch the function across.

So why do this though?

At the time, I was doing a fair bit of shooting of moving subjects, mostly birds of prey in flight amongst other things.

By using the * button with the AI servo function, it is possible to pick your subject up early, press the * get focus, maintain focus and the press the shutter button when you want to get the image.

Now of course you can do the same with the shutter button, but I found a different level of control and feel when set up with back button action.

Now my cameras have been set in this mode for four years now and just taken for granted but it can be remarkable when you explain the technique to somebody else, they go away and use it and come back and tell you what it difference it has made.

So Dinah, I am glad that you have found this to be a useful function.

As a quick reminder for 1Dmk3 users on set up.

Go into the Custom Function menu to C.Fn IV.1. Select No. 2 and save. Then if you want to focus using the * button rather than the AF-ON button, go to the next page to C.FnIV 2 and select No.1.

I prefer to use the * button as it is less of a stretch for my thumb.

Dave will let us know how it works for Nikon bodies at some point

So how about telling us if there are any tips or techniques that you have found that you wouldn't be without now.

Martin

Tips & Techniques - Highlight Tone Priority

For us Canon users and D-Light Control (I believe) for the Nikonites is a feature that can be found on the more recent bodies..

I mentioned about this feature on a forum recently and it was suggested that should feature as a blogpost - so here you go Calum!!

Firstly, I did a little bit of web searching as you do to check it out - it is remarkable how little information there actually is around. Which suggests that either people don't know what it is for, don't use it much, or that anyone has been that much interested in it.

Well I am no techno geek when it comes to some of these finer points - I use what is available to me, and try to find out it's limitations.

Using the Canon 1Dmk111 as an example, Highlight Tone Priority (HTP) can be found in the Custom Function setting, in the second group under Image/Flash exp./Disp and scroll through to C.Fn 11. You have the option to enable or disable.

I leave mine as disabled unless I am working in certain lighting and subject conditions.

So what does the manual advise us?

By using this setting, we will get improved highlight detail. The dynamic range is expanded from the standard 18% grey to the bright highlights. The gradation between the greys (or grays if you are US I guess) and the highlights become smoother.

There is a caution that with setting 1 (i.e. enabled) that noise in the shadows may be slightly more than usual.

The main visual clue is that the ISO setting on the top plate goes from upper case to lower case on the zeros. So for example ISO 400 with the HTP setting will appear as ISO 4oo. The minimum ISO becomes ISO200, as the camera is effectively carrying out a split exposure processing between the areas above and below 18% grey.

I understand that the selection of this feature will affect frame rate or buffer capacity, although I cannot confirm that from my own experiences.

Here is a bit of info I cribbed from a Google search which is attributed to the fine work by Arthur Morris on his BIRDS AS ART blog

"Canon has not publicly disclosed all the details of the method used to achieve Highlight Tone Priority. I can confirm that Canon’s method involves lowering the gain on the image sensor and modifying the image processing algorithm to simulate the ISO speed set by the user, but the details of the algorithm are confidential. Since HTP does involve lower gain than standard camera settings, it affects both RAW data and JPEG images. Although it would be possible for users to come close to simulating the effects of HTP for RAW images by shooting at a lower ISO speed and altering the tone curve of the image during post-processing, this method requires advance planning and furthermore offers no advantages in terms of noise reduction compared to setting HTP on the camera. Finally, as stated in the camera instruction manuals, “noise in the shadow areas may be slightly more than usual” when HTP is activated. Therefore, it’s basically up to users to decide if the benefits of HTP outweigh the potential drawbacks.” - all as written by Chuck Westfall of Canon USA

So does it work in RAW and jpeg. It clearly works in jpeg, and I understand to get the best of the results you should process your RAW images via Canon's own Digital Photo Professional software (DPP). This would make sense as the the software is designed specifically for Canon files.

Does it work with Adobe products to get the full benefit? Maybe somebody can answer that one. I do understand that it works correctly with Breezebrowser Pro - but you all know that Dave and I are big fans of that particular software.

Here are a couple of image that with and with HTP on. I used manual exposure to ensure that the settings remained the same. Certainly on the back of the camera, the black 'blinkies' were showing on the version that didn't use HTP. You will note that the shadows are clipped on both versions from the little blue triangle.

The main thing to note though is the shift leftwards of the highlights on the histogram with the HTP on version., and that the red clipping warning is extinguished on that version.

So when and where would I use it?

Bright light conditions, with very light subjects - so Egrets for starters, plus Kingfishers in the sunshine, when the sun is beating down on their white neck patch Calum :-).

When wouldn't I use it? - the rest of the time - as I said before I set it to default OFF.

So try for yourself and see what you find.

Without HTP (blown highlights)

With HTP on (clean highlights)

Martin

News - 1Dmk3 Update - Test shots

Further to my post on Saturday, I promised some test shots for you.

The first two are screen grabs from Breezebrowser showing the AF points lit. In each case I specifically use an off centre point, as this was one area that the 1D did not perform as well, and was mentioned in the recall note. I have to say I am happy with tis performance. Both of these images have some background clutter that was previously difficult for the camera to always separate - again no troubles here now.





The second two shots have been processed, but I have not cropped so you can see all the elements in the image that the camera had to contend with.





Again, I wanted to show performance with close background confusion opportunities. These two images are consecutive shots, taken at 5fps, my usual default for multi shots. This time I used the centre point, AI servo, 70 -200 f2.8 set at f2.8. Not particularly posted for photographic merit, but from a test perspective.




If you want to know any of my other CF settings for this please let me know via the comments and I will be pleased to help.

If you want to the images slightly larger, just click on them, but remember to press the back buton in the browser to get back here

Martin

News - 1Dmk111 recall - Final Part.......probably

Right then - I am now happy. I finally believe this is the camera I hoped that I was buying back in August 2007. Yes it has been a long time, yes it has been frustrating and to be fair has been pretty good since the firmware update in April 2008.

But this has taken the performance to where I think Canon users have been demanding.

When I did my original moving subject testing, I went to the footbridge in Stratford upon Avon to capture images of the numerous black headed gulls who respond will to bread being thrown high into the air.

So off I went with my pet tosser, of the bread, today in very bright light. Alas there were no gulls - obviously gone off to their breeding grounds now, or maybe they just don't like tourists.

Fortunately, there are also a lot of pigeons which are at least as difficult to capture.

I tried a number of different options of AF point, from full 'ring of fire', single centre point only, and also off centre points as well, with or without assist points activated. I used my 70-200f2.8L lens, set at f2.8.
At that aperture, i was not always getting my subject fully in focus across the width of the subject, but for test purposes that was fine as it helped to better define the actual focus point and plane.

So - the verdict.

As long as I got the AF point in the right place - everything was sharp. All were keepers in that respect. This is not something that I had experienced to date.

One particular area that was always trouble was when the subject was in a low contrast situation, such as a mid tone bird flying through a similar background. Well these are now very good too.

I will post up a couple of images tomorrow to back up this post.

I guess the one area that I haven't tested that I need to just be certain of is flat light low contrast subjects. So maybe I need to just hold a little in reserve until we have crossed that hurdle.

But based on use since it has come back I am very happy with it ............so far

Update: - Will post images tomorrow including screen grabs from Breezebrowser showing the AF point highlighted

Martin

News - 1Dmk111 recall - Update

Further to my last post here, I said I would update after a some testing.

Well I went up north this weekend to shoot some Red Grouse. The cock birds were definitely trying to impress the hens at this time of year and were strutting their stuff.

I didnt get as many shots as I would have liked and I still need to do some more testing, particularly on moving subjects.

All the shots that I took were off pretty static birds, using the car as a hide with the bean bag on the door of the car.

I tried centre point and also off centre. There ere a few out of focus images, but cannot be certain that wasn't operator error, so am not going to say for certain. I will do some more testing at the weekend. Probably with the highly mobile Black Headed Gulls here at the bridge in Stratford upon Avon, where I did all my original testing when we had the difficulties last year.

First impressions look and seem good and appear to have better level of sharpness. But I need a bigger sample of images to be perfectly happy yet.

But anyway, here are a couple of images from my trip.

I will do some more work on this and let you know.

Martin

News Update - Canon 1Dmk111 recall

OK here is the next instalment from this post and this post last week.

Quick recap - the recall note went out Tuesday, I responded the same day. Canon RCC Elstree called me on the Thursday and the camera was collected on the Friday as promised.

I requested it back here tomorrow and it arrived today, complete with new firmware installed, the Af system re calibrated and a new rear screen fitted as I damaged it last year, at just the price for the labour to fit.

So Canon RCC get a full 100% from me for delivering ahead of all agreed time schedules - well done to then and in particular Lauren Dicker there who has been my contact there - Thanks Lauren.

So I will be testing it over the weekend and give you another update after that to see if there are any noticeable differences, particularly in the off centre AF point focusing.

Martin

News - 1Dmk111 update

Further to my post earlier this week here, I registered my Mark111 with Canon just before I wrote that post. In the Canon registration, it said they would contact you within a week.

Well I got my call and email within 48 hours to arrange collection. As I need the camera next weekend, I requested collection on Monday 16th, to be advised that if they could collect today, I would have it back in time during next week.

So with that guarantee, the body was collected this morning and is due back by next Thursday. I am also taking the opportunity to get my rear screen replaced at the same time as I managed to scratch it while shooting Sanderling in Norfolk last year.

So, considering what 1D 3 users went through last year with the recall for the sub mirror fix, it is encouraging that Canon, at least here in the UK seem to have sorted the logistics in advance of the notification.

I know they took a real hard time last year, but I will come to the defence of the folk I have dealt with at Elstree RCC who did their very best by me. It is no good shooting the messengers - they didn't design these flaws.

So here's hoping for a quick return.

Will keep you posted on the experience as I know there are many people who will go through this and maybe have not started the process off yet.

Martin

News - 1Dmk111/1DSmk111 - AF Updates

Thanks to the feed from Blab, Canon have announced information regarding the accuracy of mark111 Af performance.

Link to Canon announcement is here for you. (for UK sites, for other countries, please check via your Country Canon support sites)

Also good news by the looks of it for the dreaded Err99 syndrome.

This is not a problem that I have ever seen with my Mark111, but I know it happened to Dave on more than one occasion.

Let us know about your experiences with the Mark111 since the last firmware updates from earlier last year.

Also good to see that Canon are not just leaving users, as I have seen written by others elsewhere.

Martin