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Author Topic: 1Ds Mk II major design flaw for landscape photos  (Read 8012 times)
Jack Flesher
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« Reply #20 on: September 30, 2004, 06:48:31 PM »
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Jack, for the record, if I do as you suggest and make a print large enough (or crop severely enough) and stand close enough, the print will look out of focus where you might expect DOF to save you.
For the record, NO IT WON'T!  ---  At least NOT DIRECTLY from original DOF problems!  

HOWEVER, since you are moving closer to the print, you alter the standard viewing distance which in turn alters the calculation for acceptable CoC.  Thus you impart NEW constraints on your CoC limits, but these issues are NOT from original DOF limitations directly, only imparted after the fact by YOUR manipulation.  

Since you also CROPPED, you actually CHANGED THE FORMAT of the sensor in question, again altering the appropriate CoC calculation.  Again, this is NOT directly a result of any original DOF limitations, only imaparted after the fact by YOUR (careless) manipulation.  

In summary, in both cases you altered the parameters that DIRECTLY affect the CoC calculation, and thus require CoC to be modified for a correct effective DOF calculation.  

The 100x focal rule holds true for all formats and all lenses.[/font]
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katovic
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« Reply #21 on: October 01, 2004, 02:29:54 AM »
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[font color=\'#000000\']That seems like alot to pay for a falty camera you should check out http://bargainfindsonebay.com/ and see about a sonycybershot maybe.   [/font]
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howard smith
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« Reply #22 on: January 06, 2005, 09:55:09 AM »
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Jonathan, it appears to me IMUO, that some confusion about DoF and CoC is created when your position is first made clear (and I believe accurately) when you state that your purpose is to make images with all parts within the DoF.  This is entirely consistent with using the smallest CoC.  I also see that a CoC smaller than a pixel makes no sense because a point smaller than a pixel will appear as a single pixel anyway.

The confusion comes in when your rule of using a CoC equal to the pixel pitch is restated without all of the assumptions.  Some of us, at least me, soemtimes wants to make an image with some elements out of focus for a reason.  Then it makes sense to me at least to select a larger CoC, namely the one that will give the priny appearance I want.

A similar thing has happened to the DoF on some camera lenses.  The lens maker assumed certain things about CoC, print size and print viewing distances.  Then, over time, those assumptions are lost, forgotten, never learned, whatever, and the DoF scale on the lenses become fact.  Well, it is fact, but for the assumptions only.

Before I get anybody all whipped up again, this is just my opinion.
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howard smith
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« Reply #23 on: January 07, 2005, 06:15:07 AM »
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Jonathan, thanks for the clarification.  If I understand you correctly, you are saying that you select a CoC equal to the pixel pitch, and define any point so out of focus as to make a spot larger than a pixel as out of focus.
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Jack Flesher
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« Reply #24 on: September 26, 2004, 03:56:38 PM »
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[font color=\'#000000\']Personally, I never used it when available on the previous 1 bodies anyway, so I don't miss it here.

Instead I prefer to set hyperfocal manually, using the DOF preview button to confirm the in-focus areas. Yes, it is sometimes difficult to determine actual focus when using DOF preview, but I am used to looking through the dimmed finder and always seem to make it work.  This probably comes from years from looking through a dim LF groundglass to determine this very thing...  

Furthermore, I never trusted the camera's pre-assigned programming to be more accurate than my actual viewing of even the preview-dimmed screen.

My .02,[/font]
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Jonathan Wienke
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« Reply #25 on: September 27, 2004, 01:22:50 PM »
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[font color=\'#000000\']DOF with digital cameras should be calculated using the pixel pitch of the sensor as the Circle Of Confusion value. That will tell you what pixel-sharp DOF will be. Using larger values will result in files that are blurry and soft-looking, and smaller values would be rather pointless.

1Ds: .00888mm
1Ds-MkII: .00721mm

I have no idea what COC value Canon used in DEP mode; I've never used it. Actually I have it disabled via a Personal Function so that my 1Ds and 1D-MkII behave exactly the same way when switching modes.[/font]
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Jonathan Wienke
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« Reply #26 on: September 27, 2004, 09:37:23 PM »
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[font color=\'#000000\']Distance measurement isn't as nigglingly important as it might seem. The distance scales on the lens are sufficient in most cases. For example, the 17-40/4L has the infinity mark just after 1 meter on the scale. The reason is that it starts getting into hyperfocal territory shortly after 1 meter and DOF is correspondingly wide. In general, the more fussy DOF is, the greater the precision of the distance markings on the lens will be. You can use a laser rangefinder if you like (I happen to have one, but I use it for other purposes) but in practice it's overkill. One thing you might consider is taking a laptop on shoots with you. You can use it to dump memory cards to, and you can have your spreadsheet handy for any shot you might want to take. If you're shooting tethered, the laptop is mandatory anyway. Another helpful thing to remember is the DOF relation between lenses of differing focal lengths. If you double the focal length, the DOF at any given aperture/distance combination will be divided by four until you approach hyperfocal distance and the numbers hit infinity. So if you print up a chart for a 50mm lens, you can use the figures for a 100mm lens if you remember to divide the DOF amount by 4. Play around with the spreadsheet and you'll see what I mean.[/font]
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mnogueira
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« Reply #27 on: September 28, 2004, 06:36:16 AM »
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[font color=\'#000000\']Read this:

http://www.luminous-landscape.com/reviews/palm_pilot.shtml

so close it could bite you !  :laugh:

I quite like it, of course you need to have a pda, but then again, who doesn't these days ?

I think it solves the problem of carrying your pc with you.[/font]
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Jack Flesher
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« Reply #28 on: September 29, 2004, 09:18:07 AM »
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[font color=\'#000000\']At small aperatures like f11 or 16, I focus to a point about 1/3 the distance into a landscape, and get sharp focus front to back on my 20"x30" landscape prints (using wide lenses on a 1Ds). Simple, but it works for me.
Dave[/font]
[font color=\'#000000\']Amen.  

More to the point, focus 1/3 of the way BETWEEN the forground and background elements you want in focus in the final image, confirm with the DOF preview button.  If you can only confirm only one point in focus due to the dim finder, the other is probably good too.[/font]
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howard smith
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« Reply #29 on: September 29, 2004, 09:53:26 AM »
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[font color=\'#000000\']I know DOF is a well defined and understood topic, but I have some questions.

1.  What is the distance that is 1/3 of the way between 20 feet and infinity?  (The distance scale on the lense barrel is very non-linear, so simply 1/3 of the distance between 20 feet and infinity isn't really 1/3 of the distance between 20 feet and infinity.)

DOF should be determined on the final print.  (Do I really care what the image DOF is in the camera?)  That is a function of, among other things, the viewing distance of the final print and the size of the final print.  For me, it is even dependent n wether I amwearing my glasses while I view the print.

2.  How does this relate to the image you see in the view finder?  The viewer is very close to the very small image, and the image in the view finder may be magnified.  If I view the small image on the back of my Sony F-707 from three feet away, the entire image usually looks sharp.  If I get really close, the image starts to fall apart.

The DOF preview shows a dim image with increased DOF on the view finder.  I believe the dimmer image will also increase the apparent DOF, the same as viewing a print in a dim room will makesit look sharper.

3.  Does the DOF preview really "preview" the final print?

4.  Does the described method allow me to predictably make a portion of the foreground or background out of focus?[/font]
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marty m
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« Reply #30 on: September 30, 2004, 08:12:13 AM »
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[font color=\'#000000\']Howard --

So, for film, what COC do you recommend for a 16x20 print that would be viewed fairly close up at a distance of a few feet?

Hopefully someone else can address the digital issue.  The COC recommended for the 1Ds is far more restrictive than any number proposed for film as far as I can tell.[/font]
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howard smith
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« Reply #31 on: September 30, 2004, 05:02:36 PM »
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[font color=\'#000000\']Jack, for the record, if I do as you suggest and make a print large enough (or crop severely enough) and stand close enough, the print will look out of focus where you might expect DOF to save you.[/font]
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Jonathan Wienke
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« Reply #32 on: September 30, 2004, 11:41:57 PM »
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Jonathan argues that the 1Ds demands a more restrictive COC than does film:

I don't think our positions are incompatible.  What Jonathan is getting at (if I may take the liberty) is that you might as well maximize sharpness since the ultimate purposes for which most folks would use the 1Ds are not 8x10 (you don't need a 1Ds for 8x10s) but larger.  If you're shooting for large framed, displayed prints the more conservative a COC you use the better.[/font]
[font color=\'#000000\']I'd say that is a fairly accurate characterization of my position. Using the sensor-pixel-pitch-as-COC means that the resolution limit of the sensor is the ultimate limiting factor to image detail rather than the focus of the lens. There's no benefit using a COC less than the sensor pixel pitch, but using COC = pixel pitch will maximixe the enlargability of the image.[/font]
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marty m
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« Reply #33 on: January 06, 2005, 08:43:43 PM »
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when I saw that DEP mode was removed, I was livid. Absolutely insensed. I was ready to take up arms and.... well, knowing I was going overboard, I went to the boards to see what the explanation was, and what others had to say.

Sadly, this didn't make things better. The "reason" for dropping it is reflected by people's indifference to it. Hardly anyone seemed to be using it. This makes sense, as it was never documented well, and that it was incompletely implemented from a user interface point of view.

Judging by the responses to the above posting, we are back to debating about how many angels can dance on the head of a pin.  This thread has been filled with long dissertations on DOF charts, but the point is that DEP is far easier to use.

Many of you have said that you'd rather carry and consult DOF charts. Talk about an imprecise and time consuming alternative. I don't have the skill to accurately judge distance at 15, 20 or 40 feet and then determine where to precisely focus the lens to obtain the hyperfocus point. And that is EXACTLY what is required when using charts. You must accurately determine the near distance (assuming the far focus point is infinity). Then you stop shooting and consult the correct chart for the focal length of your lens. Obtain the hyperfocus distance. And then focus at exactly that distance to set the focus on the lens. There is no other way to do it since detailed distance scales are no longer included on lenses. The distance scale on the 24-70 is useless in setting such distances.  You can't set the focus using the scales -- you must focus at that distance to set the hyperfocus. DEP is a snap compared to the above, and I am very surprised that more photographers haven't seen the light. I agree with Dan!

The real tragedy is the review of the MkII on Luminous Landscape. If anyone should be protesting the loss of DEP it is Michael Reichmann, since this web site is devoted to landscape photographers. In point of fact, Michael previously recommended DEP on this site and provided a primer on its use:

http://www.luminous-landscape.com/tutorials/dep.shtml

Despite that, Michael does not even mention the loss of DEP in his review of the MkII.

If a reviewer with the clout of Reichmann does not urge Canon to restore DEP in future models, then I fear that all hope is lost. And one of the most practical features that Canon has included in its cameras for the last 20 years will disappear.

Reichmann has promised his readers one more installment on the MkII, this time with his assessment of actual prints from the 4000. (I hope in a direct comparison with the camera that it replaces.)

I can only hope that Michael will strongly protest the loss of DEP in his final installment on the MkII. If he doesn't do so -- as one of the leading advocates for landscape photography -- the a wonderful feature for landscape photographers may be gone from all future models.

That would be a tragic blow for landscape photographers, given how easy it would be to continue to include DEP as an option through the functions or firmware.
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dlashier
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« Reply #34 on: September 29, 2004, 07:19:49 PM »
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[font color=\'#000000\']> What then is the distance that is half way to infinity?

Well mathematically infinity/2 = infinity  

But I would point out that the initial impulse to focus landscape shots at the "halfway" point or even the "thirdway" point is often not optimal, particularly with WA shots where the lens has a tremendous DOF. For instance with a typical DSLR, 17mm, f11, your hyperfocal point is 3.7 feet! I sometimes focus "infinity" landscape shots by focus locking on my feet   .

- DL[/font]
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Jonathan Wienke
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« Reply #35 on: January 07, 2005, 12:10:45 PM »
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Yes. That is a useful predictor of what appears "in focus" and "out of focus" in most combinations of display/print/viewing conditions. With very small prints or greatly downsampled image files, perceived DOF increases, but not always by as much as you'd think.
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marty m
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« Reply #36 on: September 26, 2004, 04:02:34 PM »
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[font color=\'#000000\']I'd recommend trying both methods and comparing the results.  The Canon DEP hyperfocusing system works very well.  (I assume Michael shares that assessment or he wouldn't have recommended it.)

Looking through a dim viewfinder at F16 using depth of field preview and trying to determine whether everything is in focus is difficult at best.  

As I said, if more photographers would try it (using the method I described and also by Michael) there would be quite a few requests that it be restored in future models.[/font]
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Tim Gray
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« Reply #37 on: September 27, 2004, 02:57:55 PM »
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[font color=\'#000000\']DOF with digital cameras should be calculated using the pixel pitch of the sensor as the Circle Of Confusion value.

1Ds: .00888mm
1Ds-MkII: .00721mm[/font]
[font color=\'#000000\']My recollection was that using the pixel size as a surrogate for the COC was somewhat controversial in that a coc that is smaller (or more conservative) than necessary is implied.  

As the sensor size goes down, the coc becomes smaller  proportionately, but I've never seen it suggested that a ff 1DS coc should be significantly different than the standard film coc of .03mm  (I've seen ranges of .027 to .035 suggested).  Any references to the contrary would be appreciated.[/font]
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marty m
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« Reply #38 on: September 27, 2004, 09:04:04 PM »
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[font color=\'#000000\']Question for Jonathan and jpoll:

I'm assuming that DEP is dead.  Canon has left it off the last two top of the line models it released.  And very few photographers appear to miss it, judging by the responses to my posting.

So I'm planning for life-without-DEP.  Several postings refer to taking "excel" spreadsheets to figure out depth of field (DOF).  That led me to Jonathan's excellent excel calculator/spread sheet posted on his web site.

However, I'm totally puzzled as to how you use it in the field.   Let's assume that you can access the excel spreadsheet on a calculator -- or that you print out those that you need based upon focal length and DOF to infinity.  And do it for a variety of focal lengths and only for the apertures that apply for 35 mm.  (That results in a one inch stack of print outs, even for only 24, 35, 20, 50, 70, 100 and 135 mm -- because I printed them out.)

You still have to be able to precisely measure distance.  For example, let's assume that I've framed a shot with the near object 20 feet away and the far object in infinity.  To use your excel chart -- or any DOF chart -- I'd first have to measure the distance to the closest object.  And do so with some precision.  That might be a rock in the middle of a stream -- which rules out a measuring tape.  Then, using your excel chart, I'd obtain the actual point to focus for hyperfocus and DOF -- which might be 40 feet.  You'd have to determine what object in front of you is at 40 feet and focus on that -- and then lock the focus and take the shot.

All of the above requires the ability to measure distances with a fairly high degree of accuracy in the field.  And you can't use the distance markings on a lens for that.  For example -- the Canon 24-70 lens only includes distances for 3 feet -- 5 feet -- 10 feet -- infinity.  It is impossible to accurately focus at 30 feet with such a lens.

The only method to accomplish the above (that I've figured out) is use a laser finder of the type used by real estate agents to measure distance -- and they cost between $300 and $500. (The cheaper distance finders use sound and would not work for this purpose.)

Am I missing something?

If you ask me DEP is a lot faster -- even using the method I described in my original posting.  But Canon has already deleted the feature, and no one appears to miss it.

So -- back to life without DEP -- and on to hyperfocus charts.  

Exactly how are they used in the field?[/font]
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EAD
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« Reply #39 on: September 28, 2004, 03:43:02 AM »
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[font color=\'#000000\']This may be of some help, though I havenīnt used it myself...

In this pageExpodisc you have a "expo depth of field guide" which seems to be a pocket-size disc with several options regarding aperture and focal distances, capable of accurately calculating the most apropiate combinations....Anybody with experiene?

That could be an answer...[/font]
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