glenn nk
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Posts posted by glenn nk
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Generally speaking, the photozone reviews give top marks for build quality for the Tokina lenses, and high marks for IQ. Their only weakness tends to be CA's, but they all seem to test in the Excellent range for MTF values.
http://www.photozone.de/Reviews/overview
I have the Tokina 12/24, and in terms of build quality and smoothness of operation, it very closely matches my Canon 24/105L.
In the photozone ratings, the Tokina 12/24 essentially comes out in a three way tie with the Canon 10/22 and the Sigma 12/24.
I personally have not experienced the CA problem that photozone mentions, but I may not have run into strong contrast edges.
If the OP has a chance to look at or try the Tokinas, it is quite likely that he will be impressed by them. In terms of value for cost, they are very competitive.
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The comments about Canon and Nikon "missing the boat" in regard to body IS are not new (not even on this forum), and have been debated ad infinitum ad nauseum, and essentially once one's mind is "in one camp", there is little chance that the mind will be changed.
That being the case, only time will tell to see if one system will become dominant.
Personally, I don't see Canon and Nikon falling by the wayside because they've chosen the lens based IS approach. On the other hand, body IS may be adequate for many users.
From a technical aspect, the lens based system has the advantage, but often technical aspects don't dominate in the marketplace. One need only think back to the VHS versus Betamax dogfight - the best technical solution didn't survive.
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An interesting link showing which lens systems will fit on which bodies:
http://forum.mflenses.com/canon-eos-and-manual-focus-lenses-t3361,highlight,register+table.html
The Olympus 4/3 bodies have the largest selection of other lenses that will achieve infinity focus, followed by Canon, etc. with Nikon and Fuji bringing up the rear and being the least flexible in this respect.
PS - don't dump the 5D yet.
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From this site, download the DOFMaster Hyperfocal Chart:
http://www.dofmaster.com/charts.html
Then install it on your computer (it will put a neat little icon on your screen).
When you run it, it will produce a chart; I have one for each of my lenses printed on light cardboard in shirt pocket size.
The options are as follows:
1. Chart size (any size you want),
2. Title, the default is Hyperfocal Distance Chart, but your lens info can be entered,
3. Short lens length/long lens length - useful for zooms,
4. Distance units (feet or meters),
5. Minimum and Maximum Distances
6. Minimum and maximum f/stops of the lens (or the ones you use),
7. Show 1/2 or 1/3 stops,
8. Circle of Confusion. Elsewhere on the site, they list the values for various cameras.
Print your chart(s).
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Seems to me that those with the 40D think it's worth the money; those with the 20/30D are less inclined to agree.
Perhaps this isn't surprising.
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At nearly ten years old, this lens doesn't have the latest IS version - newer ones will detect a tripod and will deactivate. This lens used on a rock solid tripod must have the IS turned off.
Is there any chance that this could account for the problem?
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The first time is a bit nerve-wracking for many of us, but after a few goes, it becomes rather ho-hum.
Some references to bolster your confidence:
http://www.bobatkins.com/photography/tutorials/sensorclean.html
http://www.cleaningdigitalcameras.com/index.html
http://www.dmcphoto.com/Articles/SensorBrushes/
I have used 99 percent pure isopropyl alcohol, it's not as good as the purpose made cleaner, but close.
I would not use any type of alcohol that wasn't 99 percent pure. I've found that the best source for the purer types is a drug store.
Ethyl alcohol (ethanol) and isopropyl alcohol (isoprop) are two of the ingredients in one of the best known solutions - the third being methanol:
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I didn't realize that when the OP put his lens on (50 mm f/1.4) that he or the owner had taken the lens off, opened up the shutter (cleaning mode), and breathed on the sensor.
I have no idea how long it would take for a "do-drop" to evaporate. Incidentally, I've breathed gently on my sensor as a quick check to detect larger spots - they show up quite well, as will sensor swab tracks.
Or perhaps they were cleaning it and the OP just didn't mention that, and too much cleaning fluid was left on the sensor. My sensor fluid evaporates quite quickly, but then I've never spilled a drop on it.
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I've seen and cleaned many sensor spots, but those don't look like anything I've ever seen. I've never seen dust spots that show up with a white centre.
Liquid? What is liquid doing on the sensor surface?
The little spot in the second image just below the upper red circle looks like dust but the others really don't to me.
Not only have Canon clean the sensor, have them evaluate it - those white centred spots bother me. Sorry, that's just my feeling.
Incidentally, spots or dust on or in a lens rarely if ever show up on an image. One of the lenses I have is infamous as some copies suck dust in, but no one actually has seen spots on their images.
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I had the same problem at first, but it cleared up when I started washing my face once a day in the morning . . . . . .
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I would read ALL of the review on photozone of the 24/70, not just the opening lines. The VERDICT is interesting - and disturbing.
http://www.photozone.de/8Reviews/lenses/canon_2470_28/index.htm
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I have purchased 99 percent pure iso at drugstores on at least two or three occasions - the latest in March 2007.
Don't use anything less pure.
It is often recommended for use to clean tape recorder heads and is one of the ingredients in Eclipse E-2:
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I have the lens and use a Rodenstock E77 UV/1x MC filter. The filter is thin AND is threaded to accept the Canon lenscap.
As for vignetting, the following is and excerpt from the photozone report:
"At f/2.8 the lens shows very pronounced vignetting around 1 EV at all focal lengths. Stopping down helps to reduce the problem and from f/4 it's reasonably well controlled. However, it is a weak spot of this lens".
http://www.photozone.de/8Reviews/lenses/canon_1755_28/index.htm
I've just spent a few minutes in Lightroom where I selected all my images that used f/2.8 (only two of my lenses have f/2.8 and I only checked the ones taken with the 17/55).
The vignetting in my opinion on my lens would be rated slight and many people wouldn't even notice it, even if I pointed it out.
This leads me to think that the lens does have copy variations, as photozone definitely made mention of this weakness.
However, a thick filter will worsen the effect to some extent.
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This has been on the net for a few hours:
http://clublexus.com/forums/showthread.php?t=326811
And it's causing some considerable angst.
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The links provided by "mike earussi" are worth reading carefully.
This doesn't imply that the f/2.8 isn't sharp - it's just not as sharp as the f/4. Conversely, the f/4 isn't as fast.
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There are many that firmly believe that keeping a UV filter on this lens at all times reduces the dust intake. I'm not convinced.
I've compared the sealing of 24/105 and the 17/55 by inserting a thin piece of cardboard between the barrel and the zoom ring on both lenses. The "feeler gauge" will go quite a bit farther into the 17/55 than into the 24/105 (which is a sealed lens). There is a rubbery feel when the cardboard is pushed into the 24/105.
That being said, I put a UV filter on this lens the day I bought it, so I don't know if the filter helped, or if my copy is one of the newer ones that leak less. After 10 months, no dust at all.
I believe it's been claimed that the newer copies are better than the first ones that came out, but this could be hearsay with no credence.
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f/2.8 to f/4 is only one stop - we all know that, and it can be meaningless or important, depending on the lighting situation. If lighting is not a concern, the difference between f/2.8 and f/4 is academic, but that's another topic.
For indoor candid family shots, I always use the f/2.8 lens over the f/4 one because I want to avoid "destroying the moment" with a burst of flash. The shutter noise is bad enough!
Will King said essentially the same thing in five words.!
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Shortly after I received my 30D, I went into the park to capture some autumn colours, carefully selecting the most colourful leaves for closeups.
During the shoot, I looked at the LCD monitor and was horrified that every shot was in B&W. Checked the setup, and somehow it had been set to B&W not Landscape Mode. How stupid of me, I thought.
When I downloaded the pics and looked at them in DPP, I was pleased to discover that by selecting Landscape in DPP, all the shots were in colour.
It seems when RAW is used, it doesn't matter what settings have been used - the RAW file is the same; so doing PP in Photoshop, Lightroom, or any othe program, the file that you are working with is the same no matter what the camera was set at.
This only applies to RAW files.
The difference in the friends results could be in the fieldwork, or the PP, but it won't matter what the camera is set at - the RAW file captures everything.
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As pointed out, weather sealing is not the same as waterproof, and furthermore, waterproof is not the same as air tight.
If weather sealed cameras and lenses were waterproof or airtight, there would be no lens that could be focused or zoomed unless these operations were completely internal.
It's really quite elementary - if the volume of the camera/lens combination changes, air must get in and out. The problem is in determining how and where the air gets in and out.
The comment by Mark U is interesting - the flapping mirror likely does more to redistribute dust in the mirror box than anything. In second place is the shutter curtain, which considering the speed at which it moves, is certain to cause air movement.
Particulate matter that is small enough to be almost invisible to the naked eye is dust, and will float in the air for long periods of time. So personally, I wouldn't put too much faith in "dust settling down".
Almost by definition, dust is the stuff that floats in the air for hours, not milliseconds.
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By applying some knowledge of physics, it becomes apparent that the 24/105L (I have one) is drawing dust into the 5D:
An externally zooming/focusing lens changes volume. Since nothing in the lens can significantly change volume (metal, plastic, glass, air), then the lens must draw in some air in order to zoom out.
The 24/105 lens is weather sealed (try to slip a thin piece of cardboard between the zoom ring and the barrel - it will soon encounter an O-ring seal).
Watch the rear element of the 24/105 when it's zoomed in and out. When zoomed out, the rear element moves forward (away from the mirror box). The volume of air that is immediately behind the rear element must increase as the rear element moves forward (away from the camera).
Since the lens is sealed, and the air must come from somewhere - that "somewhere" is through the camera body. Air contains dust particles (the 5D is not sealed).
It's not the 5Ds fault, my 30D lets in air the same way - it simply has to - physics.
Since I?ve been using my 100 f/2.8 Macro almost exclusively for the past three months, I?m experiencing much less sensor dust.
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At the risk of insulting the powers that be:
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Now I know where integrity went.
Fortunately, the Canon people are brighter than you think, and will recognize the grit immediately as not being part of the camera.
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The "grit" that is in your lens is simply fine particles of sand.
Some sand particles are silica (what glass is made from) which is very hard - certainly harder than the metal parts of the lens which are aluminum, and certainly harder than the plastic parts. In any event any sand particles are harder than the moving parts of a lens.
The sand particles will not come out, they are stuck in the lubricant.
When the silica particles rub against the plastic and aluminum parts of the lens, the silical particles will eventually break down into dust sized particles - somewhat good news.
The bad news is that the plastic and aluminum parts of the lens are losing the war against the sand particles. Basically you have some fine sandpaper inside your lens.
If it was mine, I wouldn't even have turned the zoom or focus rings a second time - I'd have headed to the camera repair shop to have it cleaned.
Getting grit into your equipment is not a failure of the equipment.
Sorry for the chastisement, but that is the attitude that the manufacturer will take.
The sooner you clean it without using it, the less it is likely to cost.
Do it NOW.
Why can't Canon make a 17-55 like Nikon
in Canon EOS Mount
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Yes, if the OP is using a XXXD or XXD series body, there is a 17/55 lens that is as good as Nikon's. In fact it edges out the Nikon in both CA control, and barrel distortion at the wide end.
Take a peek at photozone for inbiased results; in terms of IQ, the Canon is the winner.
Hope this helps.