SONY alpha900 vs CANON EF



Most DSLR comparisons are against other DSLR's. But I'm not the sort of photographer who keeps switching to the latest camera, be it SLR or DSLR. When I buy a camera I want it to last me a lifetime, not a lunchtime.

I recently made the transition from using a 35mm film SLR, a Canon EF, to a full frame DSLR, a Sony alpha 900. The Fx format cmos sensor "Exmor" in the Sony a900 has 24.6Mp effective 35.9 x 24.0mm with a 95% fill area, and boasts a resolution at its lowest ISO100 rating comparable to ultra-fine grain colour transparency film.

My photographic interest lies in landscapes, seascapes & skyscapes. I have been using a Canon EF fitted with either a 55mm SSC ALII f/1.2 aspheric FD breechlock bayonet lens or a Zeiss 20mm f/4 Flektagon (via an Exakta to Canon FD adapter). Prior to buying the Canon EF I used an Exakta Varex IIa all mechanical camera with a hand held Weston Master V lightmeter. The Exakta was made in 1958.

standard aspheric lens 55mmf/1.2SSCAL2 55mmf/1.2SSCAL2lens CANON EF top

The Canon EF was purchased new in 1975, and has shutter speeds from 30s to 1/1000s, and a vertical titanium blind Copal Square shutter. It requires a pair of 1.3v HD mercury button cells, which have a very long, almost indefinite working life. Metering is silicon photocell (SPC) TTL shutter priority bottom weighted average (@100ASA EV2 - 18). The lens has an automatic aperture setting "A" on the aperture ring. The metering information is presented in the 93% x0.82 pentaprism viewfinder as a shutter speed scale running along the bottom edge and an aperture scale running along the right edge. Changing the shutter speed dial on the right, concentric with the shutter cocking lever, causes the aperture indicator needle to move against the aperture scale. The metering is electro-mechanical but the aperture scale height is set mechanically via a contact pin on the back of the lens. The viewfinder pentaprism is fixed, as is the focusing screen, a centre microprism rangefinder with clear collar and Fresnel matte surround. The ASA scale can be adjusted between 12ASA to 3200ASA (ISO), on a dial concentric with the film rewind on the left. Shutter speeds between 30s (28s in reality) to 2s are electromagnetically controlled, and from 1s to 1/1000s mechanically controlled. Flash sync speed 1/125s..

CANON EF back CANON EF finder
The Canon EF body is identical to the Canon F1 except for the latter's interchangeable screens, viewfinder, and auto-winder connection (the EF has neither). It is a heavy, 1lb:12oz brass die-cast body finished in gloss black lacquer, and extremely durable. It was made between 1973 and 1978.

CANON EF top CANON EF bottom
I have always found loading a 35mm cassette into the Canon EF child's play. All one has to do is open the back by pulling up the rewind lever (automatically resets exposure counter to '-2'), drop in the cassette, run out the leader and offer it into the take up spool on the right, tighten the film in the cassette using the rewind lever until the film sprocket holes lie flat against the film advance spindle sprockets, and then close the back. You can then advance the cocking lever until the forward counting exposure indicator registers '0'. The cocking lever then locks, and you are ready to take your first exposure. This operation is so simple and fool proof it can be done in the dark.

To take a photograph you frame your subject and focus by turning the focusing ring on the lens. You then adjust the shutter speed until you have the desired aperture setting. You can check the depth of field by pressing the triple function stop down / self-timer / mirror lock upper lever in towards the lens. When you release the depth of field lever the lens returns to full aperture. As the shutter button is depressed the shutter mechanism stops down the lens iris and then swings up the instant return mirror, and opens the shutter. The mirror drops back down again the instant the shutter closes, restoring the viewfinder image.

I have always enjoyed using this camera. It is solid and robust, and simple to use, and it has never malfunctioned. I have had it serviced twice, once in 1979, and again in 1991, when the light meter and battery check indicator circuit was replaced.

How does the Sony a900 compare? Like most digital cameras nowadays it is overladen with functions and features that are supposed to make the life of the photographer less stressful, that in reaility have precisely the opposite effect.

SONY a900

The Sony a900 has a 1lb:14oz die-cast magnesium-aluminium alloy body, covered in a thin but highly durable flat black textured plastic. I prefer a smooth, polished black lacquer finish, personally. I've never cared for flat back textured plastic. However the built in right hand grip handle is well designed, being sculpted to accommodate one's fingers, which in my case it does, perfectly. Holding the grip in my right hand my index finger is ergonomically placed so as to hover over the shutter release button. Being rubberised plastic it provides a secure grip too. It just doesn't look as good as my Canon EF. Better in my opinion to have a polished gloss black lacquer body and a rubberised grip. The fashion currently is for the matt textured finish, the look I prefer being regarded as "Retro". The real reason for the current fashion in matt textured finish is because you cannot polish magnesium-aluminium alloy prior to applying lacquer, nor would the lacquer key to the alloy without passivation and priming. The body incidentally of the Sony a900 weighs just a little more than the Canon EF, and is decidedly bulkier.

I purchased my Sony a900 with the Sony 50mm f/1.4 lens. It isn't quite as good optically as the Canon 55mm SSC ALII f/1.2, but Sony do not make a faster standard lens, aspheric or otherwise, and neither does Zeiss, who do make a range of aspheric apochromatic lenses for this full frame DSLR.

The viewfinder has a 100% x0.74 coverage pentaprism with a built-in dioptre adjustment and shutter. I like the design of the pentaprism, it yields a brighter image than my Canon EF. I fitted a type L grid screen with centre square. Having interchangeable screens is an advantage in landscape photography, and a grid screen helps frame the composition, especially if it features buildings with straight verticals. The eyepiece shutter is needed when photographing from a tripod, or remotely. It is far better than the hot shoe cover which also improvised as the eyepiece cover on the Canon EF.

SONY a900 viewfinder optics SONY a900 viewfinder screen

The camera has PASM AE metering, (@ISO100 EV 0 - 18) via a 40 segment honeycomb SPC & TTL phase lock AF. It also has a High Dynamic Range option (@ISO100 12EV range EV0-20), and a 640 x 3(RGB) x 480 LCD preview and playback screen. It requires a 7.2v Li-ion 12Wh battery, mass 2.8oz, and either a CF UDMA IV memory card or Microdrive, or Sony Memory Stick Duo card. It has a vertical titanium shutter, speed range 30s to 1/8000s. Flash sync speed 1/200s. The AF can be registered to the lens scale using a unique AF Micro Adjustment feature via the camera setup menu.

SONY a900 top SONY a900 back
Taking a photograph with an automatic lens, with the lens lever set to 'A', and the metering mode dial set to 'AUTO' is a no-brainer. There are sensors underneath the viewfinder eyepiece which detect movement. When you place the camera up to your eye, the autofocus instantly kicks in and when you depress the shutter release button slightly, the viewfinder information is displayed along the lower edge of the viewfinder's field.

SONY a900 Xmor sensor frame
It comprises from right to left, a camera shake warning (the Exmor sensor is housed in a micro-gyro inertial support frame which detects and compensates for camera shake - IS lenses with piezo motor control are not required, if you do use IS lenses the IS function has to be disabled, also if you use a tripod 'SteadyShot' has to be switched OFF); '9' the number of available continuous shots, or >9 remaining exposures, <9 if fewer remaining; '*' AE lock (automatic exposure); an EV scale 3 f/stops in either 1/3EV or 1/2EV intervals (scale steps are set via the menu), with a running cursor controlled by the forward control wheel; the relative aperture value; the shutter speed reciprocal value; the focus mode; 'M' manual focus setting (if either the focus lever is set to 'M' or a manual lens is fitted); flash indicator. (Flash guns with the standard ISO hot shoe need either the Sony FA-HS1AM adaptor, or a 4-pin FS-1100 hot shoe adaptor - the flash gun's TTL metering is disabled with either of these adaptors which only function with the PASM mode dial set to 'M'. The only way to get TTL flash metering is by using a Minolta hot shoe fitting flash gun).

SSS-3D SONY a900 mirror box

With the programme dial set to 'AUTO' you cannot alter the EV compensation. Taking a photograph using 'AUTO' with an AF lens is easy, but what if the exposure is not to your liking? What do you do to gain control of the camera?

This in my opinion is where my Canon EF wins hands down. Suppose you shoot a landscape looking up a stream into the light, bounded either side by fields, flanked by mountains, and at the head of the valley there are storm clouds. The AE setting is not going to be much use to you. It over-compensates for the sky, the storm clouds look washed out, and all you can really see are the highlights playing on the water. What an experienced photographer would do is begin by selecting a suitable aperture, say f/11 or f/16, even if it meant selecting a shutter speed slower than the reciprocal of the lens focal length, and propping the camera on a wall or a post. You meter for the grass, then the sky, and set the EV in between, which is typically 1 or 2 f/stops slower than the sky reading, by adjusting the shutter speed. In my Canon EF this is very easy to do, because the shutter and aperture scales are fixed relative to the EV. You simply meter as described and open up 1 or 2 stops by changing the shutter speed. I can do this in one move.

How can you do the same with the Sony a900? By using the "+/- " stop-shift button immediately behind and to the left of the shutter release button. But, you have to be aware that on 'AE', unless you use the "AEL" AE lock button, what you are doing is changing the relative aperture, not the shutter speed. You can set up a custom exposure programme and save it in the camera's memory (in my opinion this is largely a waste of time and effort because you need different stop shifts for every change of scene and lighting). Is there a more straightforward way of stop shifting without changing the relative aperture? Not really; with the camera set on 'AUTO' you cannot make shutter priority stop adjustments directly. To set the aperture you leave the lens focus lever on 'A' and set the programme mode dial to 'A', depress the shutter release button to get the viewfinder info. and then use the forward dial to set the aperture. You then shift the programme dial to manual 'M', and adjust the EV using the forward dial. Alternatively you can switch the 'PASM' mode dial to 'S', shutter priority. However all this does is fix the shutter speed, and when you stop shift using the '+/-' button, it changes the relative aperture, which is what you'd expect. Whichever way you choose to stop shift, by keeping the shutter speed fixed, instead of a single move setting, it takes three moves. Getting control of the Sony a900 is not easier than being in control of a Canon EF (where you have to understand shutter speeds, f/stops & depth of field in order to successfully get the picture you want).

With the programme dial set on 'AUTO' the AE auto-ranges between ISO200 - 1600, or whatever ISO range you set in the camera menu. This is not something an experienced landscape photographer would wish for. The only way to fix the exposure control ISO setting is by shooting in manual 'M'. A landscape photographer would opt for a slow to medium speed film rated between ISO50 - 200. The Sony "Exmor" sensor is noisier at ISO800 and faster. To obtain the highest resolution and lowest noise the ISO needs to be between ISO100-400. Auto ISO ranging is not a sensible option for a landscape photographer. In poor light instead of using a fast film, with an ISO rating 800 or higher, a landscape photographer would use either a tripod or a bean bag, and a longer exposure time. There are exceptions, but that is the recognised practice.

I also used my Canon EF for astrophotography through a telescope. An essential feature of an SLR suitable for astrophotography through a telescope is mirror lock-up. The Canon EF has a mechanical mirror lock-up lever concentric with and immediately underneath the depth of field preview lever. You focus the image using the parallax technique and a x2 magnifying right angle viewfinder accessory, raise the mirror, take your shot and lower the mirror afterwards. To lower the mirror on the Canon EF you simply push a button at the centre of the lock-up lever's swing radius. It can be done in the dark, by feel.

The Sony a900 mirror lock-up by distinction can only be effected through the menu, accessible via the "DRIVE" button behind and to the right of the shutter release button. It is not a function that can be done in a single move. Having focused the image using the parallax technique and a x2 magnifying right angle viewfinder accessory, you depress the "DRIVE" button, scroll down the menu option to "mirror lockup" and select the option using the navigator joy stick on the camera back. When you half depress the shutter release button the mirror locks up. You then depress the shutter button further and the shutter opens. This is not a satisfactory method for taking an astrophotograph through a telescope. Normally you would use a cable release or air release, but the Sony a900 DSLR does not have a cable release female screw thread fitting. Half and then fully depressing the shutter release button requires a delicate touch and is not easy to do in the dark.

The manual recommends you minimize vibration by using the wireless Remote Commander. However you cannot lock-up the mirror using the wireless Remote Commander. Instead you have to use the 2 second delay self timer control on the wireless Remote Commander handset. This again is not entirely satisfactory because some telescope mountings may resonate for more than 2 seconds before the vibrations are effectively damped. If you lock-up the mirror via the "DRIVE" button, it takes 30 seconds for the mirror to drop. This is completely unsatisfactory. You need the mirror to drop as soon as possible after taking your shot to check the image hasn't drifted due to tracking error. This is not an issue using the wireless Remote Commander because the mirror is not locked up prior to the shutter opening. A means of locking up the mirror and dropping via a direct electro-mechanical control would have been preferable, plus a means of doing so via the wireless Remote Commander. There is one caveat to this bone of contention. Mirror lock-up can be effected manually using the wired Remote Commander RM-S1AM, but the 30 second drop delay cannot be over-ridden. I stumbled across a viable work around for this issue, the JJC JR-F Infrared Controller. It is cheap, only 18, made in China, and comprises an ISO hot shoe fitting powered receiver, and a powered transmitter. The transmitter can also be used wired. When "DRIVE" is set to "Remote Commander", & "Mirror Lockup" also selected next, then the mirror lock-up works with either the JJC-JR transmitter wired or remote.

SONY a900 mirror linkage

Whilst discussing mirror lock-up it is worth mentioning that Sony have redesigned the mirror swing linkage from a hinge to a parallelogram linkage which greatly reduces mirror slap and the swing swept volume within the mirror box. It means that lenses can be used which intrude into the bayonet mouth by an additional 2mm.

Sony offer a more restricted range of lenses than Canon, but you can obtain a manual Tamron Adaptall II system adaptor, and a Canon FD adaptor. The bayonet to focal plane (throat) depth is different from a Canon SLR. The throat depth of the Canon EF is 46.5mm and that of the Sony a900 44mm. In order to maintain infinity focus and the lens focusing scale registration the FD adaptor is fitted with an a/r coated negative correction lens 27/32" OD which reduces the back focus by the requisite 4.5mm. If either the OD of the last lens element in your Canon FD fitting lens, or the iris diaphragm, is less than 27/32", or the iris is stopped down below 27/32", the image will be mechanically vignetted. The lens also shifts the image node in front of the iris by 2mm which when stopped down will introduce optical vignetting.

The adaptor will also not accept all Canon FD lenses, teleconverters or auto-extension tubes, it depends on the prime lens maximum relative aperture. This is because the Canon FD lens uses a mechanical contact pin to engage with the aperture viewfinder scale mechanical linkage in the body throat. If the prime lens has a relative aperture faster than f/3.5, the pin height on the back of the lens is too high, and it fouls the recess groove machined into the adaptor, preventing the bayonet ring (breechlock FD fitting) or lens ring (FD-2 fitting) from engaging. I contacted Ian Broomhead, the Managing Director of SRB-Griturn, who manufactured this adaptor and following a discussion of the problem, returned it, suitably marked-up, for modification by having a shallow slot milled, concentric with the recess around the lens cell.

55mmf/1.2SSCAL2-bayonet CANON lens cap SONY AF - CANON FD adaptor

The lens is also a single non-achromatic element. It does noticeably degrade the off-axis image when the lens iris is either open or necessarily not stopped down below 27/32". I found I could not use my Canon SSC ALII f/1.2 lens because the aperture scale contact pin fouled the adaptor recess groove. I could however use my Soligor 35-105mm f/3.5 Zoom macro lens. It functioned satisfactorily in macro, but did not focus at infinity. Because the Exakta to FD adaptor uses no additional optical path distance I found I could use my 20mm f/4 Zeiss Flektagon, albeit with a focal length amplification factor of x1.2. The FD adaptor increases the relative aperture by half a stop. The Tamron Adaptall II adaptor is purely a manual adaptor. It enables you to use Tamron Adaptall II prime lenses at their native focal length and relative aperture, in stop down metering mode. I have a Tamron SP300mm f/2.8LD apo telephoto with x1.4 & x2 converters. I could use this lens with no restrictions or caveats, other than the Canon EF shutter priority function is disabled.

How do the photographs compare? I have been shooting landscapes with ultra-fine grain colour transparency film for 45 years. My most recent shots were taken in February 2008 using Fuji Velvia 50RVP. The quality and resolution of the Sony a900 set to ISO100 is similar, I cannot fault it for that. (The ISO range is 100 to 6400).

The Sony a900 DSLR is undoubtedly more versatile. I like the preview function where exposure adjustments can be made from a preview shot and then the photograph retaken and stored to memory. And of course there is the image playback function. But what I dislike is the rigmarole you have to go through to make stop adjustments when the lens is set on AE.

SONY a900 preview screen

What is it like using the Sony a900 with a manual lens? Ironically I find it far easier to get the picture I'm looking for with a manual lens. But the irony is compounded because the camera's depth of field preview only works with Sony compatible AE lenses! So you have to compose your shot just as in the days prior to automatic stop down metering! You set the lens lever to manual 'M', and the programme dial to manual 'M', frame your shot, half depress the shutter button and check the shutter speed, and then focus and stop down your lens, and set the EV compensation. Back essentially to using a film SLR in the late 50's early 60's.

Why did I choose the Sony a900 in preference to the Canon 5D MkII, when I'd been a Canon user for 34 years? I did seriously consider the Canon 5D MkII. In fact I was unaware of the Sony a900 until well after I'd decided to buy the Canon 5D MkII. So what changed my mind?

Canon FD lenses are no more compatible with an EOS DSLR than they are with a Sony/Minolta DSLR. The Canon EF to FD adaptor functions in precisely the same restrictive way as the Sony AF to Canon FD adaptor. Continuity of existing Canon lenses was not a meaningful consideration.

The Sony a900 mirror lock-up is accessible via its 'DRIVE' button, whereas Canon have buried the 5D MkII mirror lock-up in its menu, and it is equally restrictive in use.

The Canon cmos-t4 21Mp sensor has a lower dynamic range (11EV as opposed to 12EV). It has a wider ISO range (ISO50-25600) and slightly less noise. But it has lower resolution, and the Sony "Exmor" sensor noise is not significantly noisier than the Canon t4 sensor at ISO ratings up to ISO800. Also the "Exmor" has a wider colour gamut. This is not so much an issue for landscape photography, but it is for deep sky astrophotography.

The Sony a900 has IS built into the body, whereas Canon needs IS lenses to reduce the effects of camera shake. Sony's IS works with any lens that provides focal-distance information. It also works up to an additional 4 f/stops, whereas IS lenses typically only give an extra 2 f/stops. There are no wide angle IS lenses, the rear elements are too small to provide space for the piezo motors. Whereas you can obtain IS with even a 20mm lens with the Sony a900.

The Sony a900 is a stills camera, it does not have video. The Canon has HD video, with the consequential cmos staggers when panning. I'm not a movie maker, never have been, never will be. Making a movie compared to taking stills, is like writing a novel compared to writing a note. Why pay for HD video when you've no intention of ever using it? If I'd wanted a movie camera I'd have bought a movie camera, not a DSLR. The Canon 5D MkII has a fixed live view screen. How is that any real use when shooting video? A digital video camera needs a hinged and swivel view screen, preferably with touch screen menu selection. Having video on a digital snapshot camera is fine, but on a semi-pro DSLR its superfluous.

I didn't like the Canon 5D MkII's grip. It looks incongruous, an afterthought, bolted onto the jelly mould body (how I loathe the jelly mould EOS body). Nor did it fit my hand too well, my index finger had to be prised over the shutter release button which is set way too forward. The Sony a900 has what is laughingly called a "Retro" design. In other words its cuboidal, as opposed to something that looks like Salvador Dali designed it and then left it out in the Sun too long.

The Canon viewfinder is 98% x0.71, and is decidedly dimmer than the Sony a900. Why that should be is a puzzle. The lower viewfinder magnification ought to produce a bigger exit pupil, but the eyepiece is undersize. Nor is it fitted with a shutter. You have to use the hot shoe cover to prevent stray light entering the eyepiece when the camera is used remotely, just as I have to do with my Canon EF, a design from 1973.

In my opinion Canon have allowed Sony to steal a march on them in the mid-priced semi-pro DSLR Fx format market place. The Sony a900 takes equally good stills for a body only price 200 or so less. It has sensor stabilisation and instant return mirror technology lacking in the Canon EOS Fx series, and it has a better ergonomic design.


The one drawback with opting for a Sony DSLR, especially the a900 with its Fx format sensor, is the restricted range of lenses available, capable of covering the sensor's 43.8mm diagonal without optical vignetting. There are no "Super-Zooms" made for Fx format cameras, fit one and because they are DX lenses, the a900 switches to APS-C format, which in my opinion defeats the whole object of using the a900. APS-C has a field of view factor (fov) x1.5. Anyone who has grown up with 135 format film (35mm) equates 18mm with a ~104° fov not ~67°. If you're interested in wide angle landscape shots, like I am, only a lens designed to cover the diagonal of an Fx format sensor will do. Sony offer a 20mm f/2.8 94° fov, or the Zeiss T* 16-35mm 110° - 63°, but they are very expensive lenses. A landscape photographer does not need auto-focus, it can be dispensed with. I began casting around looking for manual lenses that would serve the same purpose, and alighted on the Tamron Adaptall II series. I eventually purchased a 35-210mm f/3.5-4.2 SP X6 Zoom (64° - 11° fov) Macro (1:3.8) & a 17mm f/3.5 SP (104° fov). Tamron SP lenses are every bit as good optically as the Zeiss T* & Sony G lenses, both in terms of raw resolving power, and off axis aberrations. Yet I obtained them at a fraction of the cost of their equivalent stable mates. The 17mm f/3.5 SP cost me 100, and the 35-210mm f/3.5-4.2 SP, 45. The prices included a Canon FD adaptor, so I can use them with my Canon EF, and I already have a Minolta AF Maxum adaptor so they can be fitted to the a900 without any restriction, other than having to use them in stop-down mode. The Tamron Adaptall II Maxum adaptor costs 50 if an original, or 20 if a Chinese copy.

Chris Lord

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