Monthly Archives: June 2007

Canon 5D sensor dust

Cameras, Canon 5D

Could this be the reason?

I was Googling the subject of sensor dust, which so seems to bedevil the 5D, and came across a very funny criticism by one user who may well come from eastern Europe, given the grammar. What it misses in terms of the Queen’s English it gains in clarity.

“Is vacuum pump, not camera”.

So it got me to thinking. Could the lens design have something to do with it? After all, per square inch of sensor, the 5D should gather no more or less dust than its siblings, cropped or full frame, yet the 5D seems to be a problem more often than the other models.

Part of it may be that users of the full frame sensor in the 5D are either consistently making big enlargements or pixel peeping in Photoshop just to appreciate the gorgeous definition of which this sensor is capable. Bottom line, they enlarge more, because they can, and more magnification means more dust becomes visible. On the other hand, a like-sized print from a cropped sensor camera requires a 60% greater enlargement ratio, so maybe this is not a good explanation.

Yet why is it that I can put away my 5D with 24-105mm in place – my ‘standard’ lens – only to find that sensor dust has reappeared even though the lens has not been removed?

So I took the 24-105mm off the camera and, holding the rear to my cheek, worked the manual zoom ring. Sure enough, a ‘whoosh’ of air could be felt when the ring was activated vigorously. You can gauge the stroke here with the lens set at 24mm and 105mm, respectively:


Focusing seems to generate no air rush, probably because the lens uses internal focusing. Likewise for my 85mm f/1.8 and 200mm f/2.8 lenses. By contrast, the 15mm Fisheye and the 50mm f/1.4 use traditional focusing, but the throw is so short that no detectable rush of air could be felt using the ‘cheek test’.

So let’s assume that cropped sensor Canon users for the most part avoid the 24-105 (the effective range of 38-168mm being far less useful to them than the 24-105mm on a full frame sensor). So 5D users, many of whom favor this lens, do indeed have a ‘vacuum cleaner’, or more correctly, an air pump, attached to their cameras. The only thing I cannot figure out is why 1D and 1Ds/Mark II full frame users rarely complain of this malady. Maybe they opt for the 17-40mm, 16-35mm and 70-200mm L lenses, all of which seem to have a superior reputation for dust sealing? In this regard, the 24-105mm is anything but ‘pro’ quality, though there’s no arguing with the superb optical performance.

For me the cure is probably to avoid using the 24-105mm in dusty, dry conditions, opting for fixed focal length lenses in lieu. Not very satisfactory.

Maybe someone out there has done some comparative testing of the issues and causes?

All this said, the net throughput even when sensor dust intrudes, is still exceptional, especially if a ‘roll’ needs the use of the stamp & clone feature in Aperture, which allows simultaneous removal of dust motes in the image from multiple pictures at the same time.

Ilse Bing

Book reviews, Photographers

Book review

A photographer whose vision matches that of the best, but with none of their technical limitations, Ilse Bing deserves the renaissance her work is currently enjoying. Like Cartier-Bresson she did her best work in the thirties and, like him, insisted on using the small negative Leica, even using it exclusively in her studio advertising work.

From the cover photo to the colophon, this is one splendid display of the work of a great pioneering photographer. Like Kertesz and Cartier-Bresson, there is the wonder at all things new, the joy of discovering the sheer liberating qualities of a portable, small and fast snapshot camera. Just check the picture of Greta Garbo – I’m not telling the story here! You need this book.

Everything about this book, available from Amazon, is special. Whether the great photography, the impeccable reproductions, the erudite and well written essay by Larisa Dryansky – well, the whole production exudes quality, style and perfection. The quality Bing managed to extract from the poor monochrome films of the time has to be seen to be believed. I have not encountered so exciting a book of photography in ages, and it has replaced my well worn copy of Cartier-Bressons’s ‘The Man, the Image and the World’ as the ‘book on display’ in the ancestral home.

Canon’s 20mm f/2.8 lens

Lenses

It’s nice to have a 20mm again


Chevy. 5d, 20mm, ISO 250, 1/500, f/11, 1 stop underexposed, processed in Aperture

No question about it, I miss my 21mm Leica Asph Elmarit, though who can afford one at $3k+ today beats me. The Canon 24-105mm L zoom is wonderful, if a tad bulky and heavy, and the 15mm Fisheye + ImageAlign works out to something like 12mm! So there’s a big hole between 12 and 24mm and the inexpensive 20mm Canon lens fills it nicely.

Anyway, that’s my excuse, and I’m an ultra-wide guy by nature. The Elmarit does that to you. Now this lens, at one tenth the price, is no Elmarit, but it’s more than serviceable. Plus you don’t have to deal with the crappy (sorry, no other word to describe it) plastic Leica viewfinder which, for all its cost, gives only a very rough approximation of what you will get on film. Sorry, film only for the Leica lens if you want all of its 21mm wide on the image. That disables it for me ay any price. If you want to get flare free snaps with biting corner definition at full aperture, and you are unaware that film is dead, the price of entry to the Elmarit world is justifiable. For me, this Canon 20mm f/2.8 does fine. By f/5.6 vignetting becomes very low and the corners sharpen up nicely; frankly, they’re not so great at f/2.8. At f/5.6 an 18x print will not embarass you, provided your original is sharp and well exposed.

Yes, it has some flare spots into the sun – see above – but the image retains high contrast across the frame. All I did was bring up the shadows in this snap, using Aperture. Exposure was for the highlight on the hood. Contrast is as recorded by the camera otherwise. Works for me.

A nice lens, not all that compact, and fully automatic – lightning quick auto focus (though hardly vital with a lens this wide) and easy manual override. I bought mine from B&H in New York along with an inexpensive Canon 72mm UV filter to protect that bulging front element.

Update: After some more experience I ended up exchanging the lens for another – read here.

Canon and collimation

Lenses

An intriguing new feature in the latest pro Canon DSLR

It was a rite of passage when using my rangefinder Leica bodies – the M2 and M3. Should the rangefinder alignment go out for whatever reason, you would go outside, place the camera on a tripod, focus on infinity then remove the lens. Sighting the rangefinder, lateral out-of-alignment would be corrected by using a right angled flat bladed screwdriver on the roller cam, which is eccentrically mounted. Replace the lens, check, repeat if necessary.

Vertical alignment was even easier – with the lens in place, remove the small chrome screw next to the rangefinder window on the front and use a jeweler’s screwdriver on the slotted screw thus disclosed.

This was called ‘adjusting the rangefinder’.

Much the same your friendly Leica repair specialist would do, though for your $250 you would get a three month waiting list and the obligatory German accent should you actually be lucky enough to reach this exemplar of the mechanical arts on the phone. If lucky to get him, you could plead for the return of your body after the obligatory three month absence. Good luck.

Aaah, Leica ownership. Like owning a Jaguar. You need two. One for the garage while the other is in the shop. You also need two mechanics in case one breaks down.

So lo and behold, what does the new professional grade Canon 1D Mark III offer? Why, a modern electronic version of this same feature. I quote from the awesome (as in 720 page!) B&H Digital Photography catalog which the local fork lift operator just delivered:

“AF Micro-adjustment is another example of the flexibility of the Mark III’s AF system. If a critical photographer ever finds that his system seems to consistently focus slightly in front of or behind the intended subject, the AF Micro-adjustment (C.Fn III – 07) allows the user to adjust this in fine increments to put the sharpest plane of focus back where they’d (sic) like it to be. It even allows different adjustments for up to 20 different Canon EF lenses if necessary”

So it sounds like Canon has not only added an overall adjustment to correct for an incorrectly adjusted focus sensor, they have also made it possible to key this adjustment to your lens of choice, recognizing that manufacturing tolerances would, inevitably, result in mis-collimated lenses. So you adjust things in the camera rather than at the manufacturing stage, suggesting a very smart way of keeping the cost of lenses within reason.

Now this latest Canon camera holds no interest for me. It uses a cropped sensor, making my wide angles less wide. Even if it had a full frame sensor I would not be a buyer as I simply do not need battle toughness or 10 frames a second capability, nor the massive bulk of the fixed battery grip.

But it’s nice to know that this feature will be coming to more ordinary bodies down the road, as these things inevitably do.

For some stunning Canon publicity images from this new camera, which claims a sharper sensor than its predecessor (these are clickable BIG downloads), click here. Make sure you check out Sample Image 7 – taken on the 85mm f/1.8 – the cheapest optic used and quite superb, as I know from personal experience.

About the Snap: Bermuda

About the Snap

Bermuda


Date: July, 1999
Place: Bermuda, near St. Catharine’s Fort
Modus operandi: From the seat of a scooter
Weather: Gorgeous
Time: 1 pm
Gear: Leica M6
Medium: Kodak Gold 100
Me: Stop! Stop! Stop!
My age: 47

There’s not a lot of good things I recall about 1999. I spent much of that year working for a bunch of hillbillies at a big bank in Charlotte, a city whose cuisine may be worse than even England’s in the 1960s. Not to mention the foul humid summers and freezing cold winters. And people who would say one thing to your face, another behind your back. Fughedaboutit! Before you could say “Where’s ma grits?” we were back on a one way flight to San Francisco.

Not, however, before we took a one week side trip to the lovely island of Bermuda. That, and the return to civilization later, were the high points of the year. Good British food (strange, I know, but true), French wines and Cuban cigars. There’s a lot to be said for those. Add a spectacularly beautiful place which limits tourists to 25 mph scooters, and you have a fine venue for any photographer.

One of the best was the annual cricket match between North and South, one of the oldest fixtures in sports. Another day found us at St. Catharine’s Fort, one of many built by the British to keep out marauding Americans. The Fort never fired its enormous guns in anger, the Yankees doubtless having concluded that discretion was the better part of valor.

Leaving the Fort we were tooling along when I caught the above out of the corner of my left eye. I ran back and just one click recorded the magical combination of clouds and color. This one hangs over our mantlepiece and works well in an otherwise simple room.

The lens and camera used bear comment. The body was the much unloved Leica M6, which had a rangefinder that would flare out in just about any light and a built-in meter that could only be read at eye level. Not so smart for candids. I sold it a while later with no regrets, reverting to my M2.

The lens was far more interesting.

No thanks to the jerks running my employer (my stock options, if I had them today would still be worthless – 8 years later ….) all I could afford in the ultra-wide area for my Leica was a Russian Orion 20mm, which ran me some $200 from a reseller in England! This came with a massive and very good finder and recessed all the way into the M’s body, after fitting the obligatory screw-to-bayonet adapter. Maximum aperture was a modest f/5.6. You had to reach into the lens to adjust the aperture, so forget about a protective filter. The aperture ring was hard to grasp, the settings were not click stopped and were most certainly not linearly spaced. Further, the lens did not couple to the M’s viewfinder and the finish of the whole thing would make even a Chinese tool maker blush. In other words, an ergonomic disaster, quite the worst piece of equipment from that perspective I have ever used. But it took nice sharp pictures and we got on fine for many years until more money than sense saw it replaced by the ultimate 21mm exotic, Leica’s fabulous f/2.8 Aspherical Elmarit. That’s a story for another time.