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Inspiring and Supporting Photographers of Australian Birds

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Discussions about cameras, lenses, accessories, and image-processing.

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Canon 90D impressions 4 years 2 months ago #2294

  • Ian Wilson
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The amount of back-focus or front-focus scales in proportion to to the distance to the target so at a range of 5 m you would be talking about 2.5 mm. And the acceptable range of defocus (DoF) scales accordingly so +/- 4 cm at 16 m becomes +/- 1.25 cm at a range of 5 m. Note that this is for f/4 aperture.

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Canon 90D impressions 4 years 2 months ago #2296

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One more post to show the detail available in the files. This is an 1100 by 1000 crop, converted to monochrome. Notice detail in the skin surrounding the eye, as well as the brick work in the reflection in the pupil (which is even more obvious in the raw file). ISO 800, 400mm, 1/100s, f/5.6.
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Canon 90D impressions 4 years 2 months ago #2297

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Apologies that should read an approx 1600 by 1500 px crop which was then reduced to 1050 vertical as per normal BLP size.

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Canon 90D impressions 3 years 10 months ago #2421

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I thought I would add my impressions after several months use of this camera, although not as heavily as I would have liked due to drought, fires and Covid. Note my use has been almost exclusively with the Canon 100-400 mk 2.

Early impressions of image quality continue to be borne out. Resolution at low ISOs is excellent, as would be expected from a modern high megapixel sensor. The files process very nicely from Raw, and the noise is easy to deal with (I use DxO Photolab). The extra megapixels do give me a bit more cropping room compared to 24 Mpix, although its not a game changer. Pretty much all raw programs now recognise the files, including the basic Windows file manager (which took a while!). In my experience, the sensor is pretty good up to about ISO2000. Go to ISO 2500 and you will notice a difference in resolution and sharpness ie you seem to cross a boundary after about ISO 2000 - I think these results are pretty typical for an APSC sensor. DxO cleans up the noise well at high ISOs, but side by side you can see a difference in ultimate resolution between something at or below ISO2000, and ISO2500. From memory this is at least as good as the 80D 24 mpix sensor.

As reviews have indicated the sensor is not 'iso invariant'. In my experience you cannot shoot at low ISOs and then add 4 stops in post processing - the result is a mess. However, it tolerates a little underexposure with little penalty making it easy to shoot for highlights.

There has been quite a lot of criticism about autofocus on this camera in online forums and in reviews. I expect at least some of this is from those who wanted the 90D to be the 7Dii replacement. I haven't got to do a lot of work on birds in flight, but for every day use I find the viewfinder autofocus to be fine, and its not something that causes me concern. I have turned off all the 'smart' aspects of viewfinder autofocus, including things like face recognition, so that it is only using the basic phase detect functions. I havent done any scientific tests of course, but it feels like these sorts of computationally intense additions to autofocus are just slowing the camera down and making it less reliable. They don't add any value for birds and seem aimed at trying to make the viewfinder function more 'mirrorless-like'. I use single point focus in one shot mode, and the 9-point mode for tracking, and have not observed too much by way of problems. I also use the 'burst and refocus' approach, refocussing often on the target. I generally use the slower continuous shooting mode, as I find the rapid fire fast mode (10 shots per second) is not normally necessary. This may help with autofocus reliability (10 shots per second with continuous autofocus is quite demanding of the autofocus sensor). For those who want good tracking and good face detection, the live view mode works very well.

After a bit of trial and error I have found that centre-weighted exposure metering gives very reliable results for general photography, and is less variable than Evaluative mode.

Ergonomically the camera is good, and the balance with the 100-400 is fine. The handgrip is nice and deep. There is a joystick, but it is pretty much useless except for moving the focus point around, and it can be easy to bump. On the other hand, re-centring the focus spot is simple as you just press on the joystick, which falls nicely under your thumb.

I wish that Canon would find a better location for the back focus button as it is pretty useless for me. I find when I press it, my thumb knuckle keeps bumping on my spectacles, leaving smudges. Its both too high on the body and too small. It rules out back-button focus as an option. The other thing (probably common to other Canon cameras, and the same as the 80D) is that there is no dedicated exposure compensation (+-) button (compared to, say Nikon and my old Sonys). To apply focus compensation when in manual mode/auto ISO you need to hold down the centre button on the back wheel with your thumb, and then simultaneously adjust with your finger on the front ratchet wheel. What the hell! Also, while on general Canon rants, my 100-400 doesn't include a focus-hold button. As far as I can work out, if you want to stop autofocus you have to assign the function to a button on the body, which then has to be held down. A button on the lens would be much better (a la Sony).

Battery life is good in viewfinder mode. No problems so far with the camera in terms of sealing and general robustness. General operation and menus are pretty much standard Canon, based on my experience with the 80D. I strongly recommend any user get the full version of the manual to get proper explanations of all the functions in the menu (pdf download).

All in all, its been an easy camera to live with. My early impressions were that Canon was trying to make a 'mirrorless Dslr' with this, and my view on this hasn't changed. It sits in a slightly odd place, trying to be a DSLR for DSLR devotees, and a mirrorless equivalent for those who use the back screen and do video. I can see why some reviewers reached the conclusion that in some ways it functions better as a live view experience, because Canon seems to have tried to make the DSLR functions emulate the mirrorless experience particularly around autofocus. Certainly there is a set of live view functions that it does very well provided you can live without the viewfinder. As a DSLR user, I prefer to turn off as many of the 'smarts' as possible and simply use it a manual or near-manual photographic tool producing raw files, and it functions pretty well.

Simon
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