Where Does a Lens Calibration ‘Out of Range’ AF Adjustment Leave You?
Box Shifters and Jobsworths
There seems to be a growing trend that is divergent in the extreme. We all know about the legendary customer service offered on line by Amazon, over the phone with First Direct. These unfortunately are rarities.Whilst clearly at the top of their game they also have few comparable competitors. In uncertain economic times (3 years of the B-word is enough for Brexiteers and Remainers alike!) there is a natural tendency to tighten a belt a couple of holes and cut back on service. Those one time knowledgeable sites or shops become ‘box shifters’ . A take it or leave it attitude.
Costs more, takes longer
Imagine you fear your camera gear may need calibrating. Not sure but your hit rate of pin sharp images is way below what you would expect. Cameracal is not the only company to offer calibration. We obviously are not the only company who uses Focal calibration software. You send your gear in, it’s calibrated and sent back. The process was carried out, there is a report that shows it. But your gear is not back to optimum performance. Something to do with being so far out of range it can’t be calibrated and you are out of pocket and likely looking at a pricey repair bill, a lengthy wait and another calibration once repaired.
Here at Cameracal we have probably carried out more calibrations than anyone else in the country. This has given us considerable insight into the problems that can arise when focus testing. Not always only relating to calibration but many other factors too. Couple the knowledge and experience of our technical team with strong working relationships we have forged with many experts in the field of photographic technology we are uniquely positioned to give the best solution to any problem you are experiencing with your photographic equipment.
Time listening saved in finding solution – “Tale of Two Bodies”
Q. What happens if I have a lens / camera that cannot be calibrated / is outside of range?
A. As long as the camera / lens combo is supported by our software solution – please refer to the following list of Canon compatible cameras / Nikon compatible cameras / Sigma compatible lenses / Tamron compatible lenses– we are confident that we can provide a solution to virtually all problems encountered.
Here at Cameracal rarely do we see a lens / camera combination that cannot be calibrated / corrected via our tried and tested software solution. We do however see combos that are just within adjustable tolerances as in + – 20 micro adjustments.
HOWEVER, we recently had a customer bring in a couple of cameras including a trio of expensive top end zooms and prime tele lenses which needed a little more than just our standard calibration service, his kit consisted of the following:
2 x Canon Eos 1Dx Mk 2 bodies
1 x EF 200-400mm F4 L IS USM + integral 1.4 x
1 x EF 70-200mm F2.8
1 x EF 800mm F5.6L
Canon 1Dx Mk 2 Body One
We successfully calibrated the first body to all lenses with the most adjustment required was for the 70-200mm and 200mm which was +12 adjustment required (which meant the camera /lens combo was front focusing (focussing closer in front of where the focusing point was positioned).
Full results were as per follows:
EF 70-200MM F2.8 = (70mm) +7, (200mm) +12
EF 200-400MM F4 = (200mm) +1, (400mm) +4
EF 200-400MM + Built-in 1.4 x converter (280mm) 0, (560mm) +2
EF 800mm F5.6 = +5
Canon 1Dx Mk 2 Body Two
However, when it came to calibrating the second 1DX Mk 2 body, the results were VERY different, with results using the same lenses as below.
EF 70-200MM F2.8 = (70mm) +34, (200mm) +56
EF 200-400MM F4 = (200mm) +14, (400mm) +34
EF 200-400MM + Built-in 1.4 x converter (280mm) = +15, (560mm) +20
EF 800mm F5.6 = +17.
Clearly there was a problem!
The only lens that could be fully corrected was the 800mm but only just (given that tolerances can be applied to a factor of + or – 20 micro adjustments).
This also meant that going forward any additional lenses that where added to this camera body would need a significant amount of adjustment and would not yield acceptable results out of the box.
What did this mean?
By way of the customer having two camera bodies as opposed to one, resulted in two independent tests being undertaken. This helped determined the problem lay with the second body and in this case the enormous displacement of the AF sensor in the camera.
Rarely do two models or in this case, two identical models return the same results (in terms of the amount of +/- correction required) but to see such a difference pointed towards a problem with the second camera and in this case with the displacement of the AF sensor which is housed below the mirror box.
We all right or wrongly assume then we purchase an expensive piece of photographic kit (be it a camera body, lens or both) that it should yield nigh on perfect results “straight out of the box”. Unfortunately even though manufacturing techniques have improved beyond recognition since the advent of manual focus film cameras of the 60, 70’s and 80’s and 90’s there are still tolerances and these tend to vary from manufacturer to manufacturer (these tolerances will be explored in a more detailed blog along with our list of recommended lenses to check / calibrate). The advent of auto focus and more recently digital has resulted in the end user being able to determine and experience these “tolerances” in terms of issues of front or back focus.
Now we are aware of these tolerances where do they (if applicable) lie.
1. More often than not front or back focus issues lie with lenses that we place on our cameras. Lens optic displacement is often a common problem and can either occur at time of manufacturer or at a later stage as result of general wear and tear or from the lens physically receiving a jar or having been knocked or dropped.
2. ALL Mirrored DSLR utilise a separate AF sensor that is housed beneath the mirror box, displacement of this sensor can cause front or back focusing issues. This can be again from manufacture or from the camera body having been knocked or dropped.
3. A combination of the two which is often the case. This can be seen when calibrating the same Len(s) to two different bodies (be it two different / identical models). The differences between the two values is more than often down to the AF displacement of the AF sensor in the camera body.
The reason for the huge disparity is more often due to the camera having received an impact / been knocked or dropped. (By way of the tank like build like quality of the 1DX Mk2 a pretty hefty impact). Armed with the hard data, we contacted the owner only to find that one of the camera bodies had indeed received an impact, having been dropped from a considerable height.
What would have been the result if only one camera had been brought it? How would we have determined if it was camera or lens related you may ask?
In this case we would have studied the data produced by the tests (several factors can point towards lens problems). In addition we have at test body with we use as a bench mark (this AF sensor having been perfectly set). These two factors would clearly determine if the problem lay with the lenses or the camera body.
As previously mentioned, in over three years and over 7,000 individual calibrations we have yet to be unable to deliver a solution to ANY problem we have encountered.
We are partnered with one of the few repair agents in the UK able to offer the next stage of adjustment. This consists of plugging the camera into a bespoke Canon solution (only available to CPS centres (Canon Professional Services / approved repair agents) to run a battery of tests and to make minute adjustments to the AF camera sensor.
Not only were we able to deal with this from start to finish but also to offer a turnaround service enviable to even Gold CPS customers (including evaluation, supply of an estimate, ordering and fitting of parts). Even though our customer was a working professional, they were not a CPS member, let alone a top tier gold level.
Once returned we again undertook calibration of the lenses with the results as follows. In this case, the values resulted in corrections needed to compensation in the optic displacement of the lenses as the corrections applied by our repairs ensured the camera’s AF sensor array was perfectly positioned.
EF 70-200MM F2.8 = (70mm) +6, (200mm) +10
EF 200-400MM + Built-in 1.4 x converter (280mm) = +12, (560mm) +9
EF 800mm F5.6 = +5
To compare the results see the table below!
So if you are encountering problems with your photographic equipment, recently added to your kit or simply have a nagging feeling it might NOT be your photographic expertise then give us a call or drop us a line!