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The DOF Scale Is Wrong

Discussion in 'Fuji X100 Forum' started by Streetshooter, Jun 26, 2011.

  1. Streetshooter

    Streetshooter Administrator Emeritus

    Jul 12, 2010
    Philly, Pa
    Well, I'm not a picker a part kinda guy. I love the camera and the new firmware is a big improvement. I noticed some time ago that my mind was playing tricks with me.
    I set my camera for say, f11. I set hyperfocal distance with MF and then I get a kinda sick feeling.
    The DOF scale is wrong. I never mentioned this because I thought it would raise a ruckus. Well.... Here it is in all it's glory. The battle begins now!

    It seems that Fuji used a 35mm lens to set the DOF scale. It should have be set with a 23mm lens instead. Use any DOF calculator and you will see what the issue is.

    Maybe Fuji was being conservative but the general consensus is, no, they are wrong.
    I did research on other forums and low and behold, I'm not the only one to spot this....

    Don't post and tell me I'm crazy until you compute the DOF on a calculator.
    This is one of the most important features on this camera and for all real purposes, it's really useless....
     
    • Like Like x 1
  2. Country Parson

    Country Parson SC Top Veteran

    682
    Apr 5, 2011
    North Carolina
    Dan
    I have not tried hyperfocal settings with the X100, but I believe you. So what is the solution? :dash2:
     
  3. Ray Sachs

    Ray Sachs SC Legend

    Sep 21, 2010
    Not too far from Philly
    you should be able to figure it out...
    I agree, but I've checked the same thing on my LX5 and it does the same thing, regardless of where you have the step-zoom set. The DOF is always less than a DOF calculator will tell you it is for that focal length / aperture combination. I haven't tested the GRD3, but it seems less conservative just based on the amazing DOF it shows for 1.5 meters in the snap focus mode. It looks infinite compared to the same essential setting on the LX5. So I'm guessing it IS about being conservative, since "acceptable" focus is such a variable concept. Rather have someone who understands hyperfocal and zone focussing use it as they wish, but protect the unknowing user who may stumble across it from thinking the areas at the edges of that DOF scale are gonna be really sharp. Of course the downside is if you use it for hyperfocal and adjust focus until the long end of the scale touches infinity, you're actually focussing a bit long of the hyerfocal point and missing more focus in the foreground, which is great for landscapes but sux for street shooting. But that's my guess about what they're doing. It was raised a lot when the camera first came out and if it really was a goof, I think it would have been one of the easiest things to tweak in the FW, but they didn't touch it, right? I almost never use the X100 in hyperfocal, but on the LX5, I just got used to leaving a gap between the long end of the DOF scale and infinity knowing that then I was probably getting very close to hyperfocal and getting a bit more in focus on the short end. I actually did a minor experiment of visually confirming focus as well as possible on the actual hyperfocal distance for say, f5.6, with the aperture wide open at about f2, then stopping it down to f5.6 and seeing where the DOF bar was. I did this for a couple of zoom levels and it always left about the same amount of gap between the long end of the scale and infinity, so I just started setting it that way. I'd do the same with the X100 if I used it that way, but I seem to save that kind of shooting for the small sensor cameras in good light where the DOF is so nearly infinite to begin with.

    -Ray
     
  4. Streetshooter

    Streetshooter Administrator Emeritus

    Jul 12, 2010
    Philly, Pa
    To answer a PM.
    Hyperfocal Distance does not change the far distance at any given fstop.
    Infinity is the constant. What changes is the near point of focus at any given fstop.

    You set HD for how close you want your DOF the be to you. This determines the fstop you will want to use. So changing fstops just changes the near range of your DOF.
    The camera is way off in the scale.
     
  5. Streetshooter

    Streetshooter Administrator Emeritus

    Jul 12, 2010
    Philly, Pa
    Ray, I do get what your saying but the point is that the camera has a design flaw.
    It's not designed for the casual shooter. It was never advertised as that kind of camera.
    A camera that addresses issues serious shooters want/need should not take something so crucial as DOF as casual.
    Fuji saw fit to make 1/3 stops because it's shooters needed that accuracy.
    They put a scale in the camera so that you could lock MF, use the scale and know where you are in the DOF range. Just because other cameras do the same thing doesn't make this mistake correct. I have tested this in a serious way and a DOF calculator is always right.
    Try as they may, Fuji can't reinvent physics.
    They can fix this easy but will they....?
     
  6. Ray Sachs

    Ray Sachs SC Legend

    Sep 21, 2010
    Not too far from Philly
    you should be able to figure it out...
    I agree its wrong - the only question being whether they saw a benefit in doing it that way or not. Clearly a lot of the camera's owners don't see any benefit. I don't either - I was just guessing as to their possible thinking. I suspect if they were gonna fix it, they would have done it in this update. I gotta figure that this would have been a MUCH easier FW tweak than some of the things they DID address in this update so if they didn't address it this time, why would they in the future? They were definitely aware of it. So I suspect they don't see it as a problem, maybe even seeing it as a feature. And if I was using the camera that way, I'd work around it by using MF to get critcal focus as sharp as I could wide open for the calculated hyperfocal distance at f8 and f11, stop down to the target aperture and see what the DOF bar looks like. And set it based on that visual in the future. As I did as a workaround with the LX5. Whether THEY see it as a bug or intentional, WE just have to work around it because at least until the next FW update, it is what it is. And I suspect even after the next FW update, whenever that will be, it still WILL be what it is today. I'd love to be wrong but I'm not holding my breath...

    -Ray
     
  7. Streetshooter

    Streetshooter Administrator Emeritus

    Jul 12, 2010
    Philly, Pa
    Luckily enough on the iphoney, I have a cool DOF program...
    So, it's just another step for mankind to find the next image.
     
    • Like Like x 1
  8. Bugleone

    Bugleone SC Regular

    113
    Jun 1, 2011
    England
    I just read this interesting topic and, although not a fuji user, feel drawn to comment,...appologies!

    Firstly, depth of field is NOT a scientifically derived mesurement, contrary to what many people believe. The depth of field scale is actually only a guide, and different groups of 'interested viewers' have different standards of what they consider to be adequate fields of sharpness.........

    For example; it used to be the case that the German and Japanese optical makers had different ideas about 'how much' depth of field was required,...German lenses had a much tougher spec than Japanese so the Japanese lenses apparently had greater DOF although their lenses performed the same in a given application.

    DOF is determined by many factors, not least by the size of enlargement in the print, how that print is exhibited and even how viewers of that print are permitted to view! For serious work it is vital that individual photgraphers carry out their own DOF 'calibration' and read/mark their DOF scales appropriately.

    Without getting too technical, DOF is suposedly determined by the 'size of the circle of confusion'.........if a point light source is focussed on an image plane, that plane can be moved back and forth and the image of the point of light will enlarge as it goes out of focus,.....this amount of movement before the point of light becomes 'too blurred',..ie the circle of confusion arrives, is the amount of DOF. The trouble is that different folks have a different perception of the 'circle of confusion' and measure it differently.

    The fuji is a very expensive (some might say "too expensive") camera and it's entirely possible that its designers assumed a more stringent standard required by its potential users.
     
    • Like Like x 1
  9. I rarely use the hyperfocal distance as it usually doesn’t give the best results.

    I consider the closet thing I want in focus, then the furthest and pick a point 1/3rd from the closet focus. For example, if you want to optimise focus between 1 metre and 10 metres, you would focus on 4 metres.

    Of course if what you want sharpest is expected to be 2 metres away, pre-set the focus to 2 metres.

    I consider that hyperfocal distance is more a tool for people who design fixed-focus cameras and want to provide a compromise between near and far and that is exactly what it is.
     
  10. Streetshooter

    Streetshooter Administrator Emeritus

    Jul 12, 2010
    Philly, Pa
    Well gentleman we can agree to disagree.
    The point is... There is a theory at hand.
    Hyperfocal distance changes the near point of acceptable focus. The constant is infinity.
    The scale is way off on the near end. Which also means it's off on the far end.
    As Peter uses a zone focus, this also is off in both directions.

    I will post the measurements later today as I dont have the camera at hand.
     
  11. BBW

    BBW Administrator Emeritus

    Jul 7, 2010
    betwixt and between
    BB
    OK, here we go. The Fuji X100 using manual focus and hyperfocal distance vs the Depth of Field program face off.

    Don has asked me to post these findings since I have the camera at hand and also a laptop to type on. Here are my readings off the X100 and Don's readings from his DOF program.

    X100: f/16 6 feet to infinity
    DOF program: 2.9 feet to infinity

    X100: f/8 12 or 13 feet to infinity
    DOF program: 5.8 feet to infinity

    X100: f/4 25 feet to infinity
    DOF program: 11.8 feet to infinity
     
  12. The idea behind hyperfocal distance is to give you the maximum depth of field, not the sharpest image.

    As the hyperfocal distance is the closet point of acceptable focus when focussed on infinity, changing the point of focus to the hyperfocal distance therefore means infinity will only be just acceptable focus. Ideal for achieving maximum depth of field but not maximum sharpness. Maximum sharpness will always be the point on which you are focussed.

    There are many situations where using the hyperfocal distance doesn't quite add up. A landscape without foreground interest for example, shooting the moon etc.

    Other than going for maximum depth of field, using the hyperfocal distance is great when you don't know where your focus point will be and cannot focus, e.g. due to low light, moving subjects etc.

    Calculating the depth of field is purely a little bit of applied mathematics and for any given focal lenght determined by the size of an acceptable circle of confusion and of course the aperture. My 1958 editon of the Ilford Manual of Photography has a few pages on calculating it.
     
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  13. It would appear that the camera's setting are based on a smaller circle of confusion compared to the software. It doesn't mean the DOF scale is wrong.
     
  14. Streetshooter

    Streetshooter Administrator Emeritus

    Jul 12, 2010
    Philly, Pa
    Peter, verified info...
    Fuji used a 35mm lens to calculate the DOF scale.
    Wrong is wrong.
     
    • Like Like x 2
  15. Still, if the value for the circle of confusion is changed, the hyperfocal distance changes. I have come across arguments for using a smaller circle of confusion value for cropped sensor cameras based on their greater pixel density and also for using smaller circles of confusion when you increase the number of megapixels in the same sized sensor.

    This calculator Cambridge Colour Hyperfocal Distance Calculator not only takes into account the sensor size but also the print size and viewing distance. The key is "what is acceptably sharp". There isn't a right or a wrong. Other calculators I have seen use values for the size of the circle of confusion like 0.02mm for a cropped sensor camera and 0.03mm for a full-frame 35mm camera. My Ilford manual just gives an example (but no recommendation) of using f/1000 where f is the focal length.
     
  16. Grant

    Grant SC Veteran

    249
    Nov 12, 2010
    Lunenburg Nova Scotia
    right!
     
  17. Grant

    Grant SC Veteran

    249
    Nov 12, 2010
    Lunenburg Nova Scotia
    My first car was a used Beatle. I loved that car with a passion as it allowed me to move further afield than I ever was able to on foot. The only thing was it was so buggy. After a while I got use to all the bugs and they became a sort of bad of honour, “I could get the most out of my bug, I could fix my VW!” Later I got newer and much better cars but I never again had a love affair that matched the one I had with my first car.

    Now that I am older along comes the X100. Nothing about this camera impresses me at al, nothing I have read, nothing I have heard, and noting I have seen impresses me at all. Still, I suspect if I bought one I would love it like my old beetle. On the other hand I know you can’t go back so the question is, “Should I?”

    I close the Fuji X100 brochure and but it down … just not too far out of reach.
     
  18. Streetshooter

    Streetshooter Administrator Emeritus

    Jul 12, 2010
    Philly, Pa
    In life we have what's called common acceptable standards.
    Every camera and lens manufacturer including Fuji has subscribed to this principal regarding DOF on lenses. Look at any lens with a DOF scale and you say...ok..this is acceptable to me.
    Here's my DOF at any given focus distance and fstop.

    So Fuji doing this along with everyone else up to the X100 has used the common acceptable standard. Why change now?
    They made a mistake. That's why.
     
  19. Armanius

    Armanius Bring Jack back!

    Jan 11, 2011
    Houston, Texas
    Jack
    I suppose the good thing is that Fuji erred on the "good" side then? Good side meaning that the DOF is actually wider (or is it deeper) than what Fuji is representing on the camera screen. So the user may be pleasantly surprised to get more subject matter that's within the DOF that he or she anticipated. Unless of course, he or she did not want that additional stuff within the DOF.
     
  20. Streetshooter

    Streetshooter Administrator Emeritus

    Jul 12, 2010
    Philly, Pa
    And if you zone focus and want a certain amount of DOF.....?
    And if the error is lens related... Infinity is not infinity...
    Hmmmm