archive-ca.com » CA » D » DIGITALCAVE.CA

Total: 28

Choose link from "Titles, links and description words view":

Or switch to "Titles and links view".
  • The Digital Cave - Misc. Circuits
    Review EXIF Stats Workflow Tools Search Contact Me Misc Circuits Included on this page are various small circuits I have created over time Some are trivial some are a bit more complex but hopefully all are useful in a variety of projects Most include both the schematics as well as the source KiCad files Digital Capacitance Touch Sensor This is a touch sensor with adjustable sensitivity which will output a

    Original URL path: http://digitalcave.ca/resources/hardware/circuits.jsp (2014-10-09)
    Open archived version from archive


  • The Digital Cave - Serial Communications
    CLS Flash Trigger AVR Libraries PSX Controller Driver Hardware Misc Circuits Serial Links Security My PGP Keys Photography Katzeye Review Extension Tubes Review Sigma 30 1 4 Review Sigma 50 1 4 Review Sigma 50 150 2 8 Review EXIF Stats Workflow Tools Search Contact Me Serial Communications Serial Console Frequently I find myself in need of a serial console which I can use to troubleshoot interact with various embedded hardware devices I recently found a hint on how to use the program screen to do this All you need to do is start screen with the arguments For example to interact with an Arduino device configured to run at 9600 baud you could use the following screen dev tty usbserial A200294u 9600 Once you are finished type Ctrl A followed by Ctrl confirm exit with y Serial Dump To dump the data to file add the L flag to the command screen L dev tty usbserial A200294u 9600 This will write all output from the serial port to screen 0 in the current directory Serial Upload I have not yet figured out a generic way to send a sequence of bytes as found in an arbitrary file over a

    Original URL path: http://digitalcave.ca/resources/hardware/serial.jsp (2014-10-09)
    Open archived version from archive

  • The Digital Cave - PGP Keys
    PGP Keys Photography Katzeye Review Extension Tubes Review Sigma 30 1 4 Review Sigma 50 1 4 Review Sigma 50 150 2 8 Review EXIF Stats Workflow Tools Search Contact Me PGP Keys PGP Pretty Good Privacy is an encryption and document signing system which allows you to allow only certain people to view documents and or verify that a document has been sent by a certain person and not

    Original URL path: http://digitalcave.ca/resources/security/pgp.jsp (2014-10-09)
    Open archived version from archive



  • The Digital Cave - Katzeye Focusing Screen (for D7000) Review
    due to their location they are based in Taiwan so shipping would be fairly lengthy Plus in the event that I needed support I figured that the language barrier may be a problem So I decided to go with Katzeye The total cost ended up being about 130 including shipping to Canada by size it was probably the most expensive piece of glass I have ever bought and that is coming from someone who wore glasses for a number of years Before we go any further and since an entire page of text is boring at best I will give you a sneak peek of what is possible with manual focus and a Katzeye screen this was taken using my Tamron 300 2 8 Nikon D7000 Tamron 300 2 8 f 4 0 1 3000s ISO 560 Installation Installation was not too difficult although it is not for the faint of heart Katzeye provides you with a small tool which looks like a flatheat screwdriver with a chip taken out of the blade this lets you carefully remove the wire clamp from the focusing screen to release the old one and then reattach it to the new one They have instructions customized for your camera which I found to be well written and accurate In the end it took me a couple of trys to get it just right The OEM shim was persistently sticking to the old screen and it was difficult to get it in place without touching either the old or the new screens During the process I actually got a spec of dust inside the screen it is at the bottom edge of the screen though and is not objectionable so I ended up just leaving it instead of trying to get it out and possibly make things worse Results I am very happy with how this has turned out The screen makes focusing with old lenses not just possible but actually easy I am still not nearly as fast as a good AF system but the accuracy seems to be just fine and I am sure that with more practice I will continue to speed up The overall screen brightness is good for f 2 8 and faster lenses My 18 105 gets a bit darker than before at the long end although I knew that going into it but even at f 5 6 it is still usable Their claim of the split screen not blacking out as early as before is true when compared to my FM2 which is almost unfocus able at f 5 6 but I would definitely not want to try focusing manually at that f stop unless I was in very good light On their website they list usable f stops for the Katzeye Plus which is included by default on all screens this is different from the Optibright treatment which costs extra The chart indicates that minimal attention is required down to f 9 0 and that careful

    Original URL path: http://digitalcave.ca/resources/photography/katzeye.jsp (2014-10-09)
    Open archived version from archive

  • The Digital Cave - Extension Tubes Review
    the combination gets quite awkward I would not want to use this in the field at all even indoors on a tripod is difficult at best I did get FEE error a couple of times The problem was that the stacked tubes if turned one direction lost enough of the AI indexing tab distance travel to make the camera think that the lens was no longer in max aperture position I would think that if this was a persistent problem on my own tubes that I could add a spacer shim to the AI tab on the tubes to recover the extra 0 5mm or whatever is needed When the TC is added the FEE error is even more common When handling the thing in real life rather than just playing at the office the entire contraption does feel a bit more unwieldy You can definitely use it in the field but I would not want to carry the camera lens like this I would put the tubes on when they are needed and take them off after the fact Below are some sample images The first two are of a ruler manually focussed at the closest possible focus distance to show magnification ratio The first is just the 300 4 all three tubes the second is the same plus a 1 4x TC Next are some shots to test the AF of the lens tube combo Again all these shots are from the 300 4 all three tube combo 68mm of extension They were shot from a monopod with flah to keep shutter speed high enough Aperture was wide open f 4 As you can see here the AF is just about perfect even with the tubes When using the 300 4 plus tubes the biggest problem is the amount of movement in the tubes While objectively it is not much it can be enough to produce the FEE error and with a 30cm lens plus tubes combination even a small portion of a degree of shift can give noticeable movement at the end of the lens In the event that I end up buying these tubes I will seriously consider crazy glueing the tubes together staying away from the screwdriver AF contacts and the aperture levers of course That should reduce radial twisting which cause the FEE errors as well as slightly reduce the wiggling of the lens up down and right left Other lenses I figured that I may as well take a look at other shorter lenses with the tubes as well since more users will probably be using moderate normal or short telephoto lenses with extension tubes I have a few options and will be describing my results with various lenses First is the 50mm f 1 4 AI S This lens can give you decent macro results with the extension tubes Below is a shot from a tripod at f 1 4 As you can see this gives you about 1 48 1 magnification

    Original URL path: http://digitalcave.ca/resources/photography/extensiontubes.jsp (2014-10-09)
    Open archived version from archive

  • The Digital Cave - Sigma 30/1.4 (for 4/3) Review
    by many a bit wider but half a stop slower I had originally tried out the Nikon 35 1 8 and found it to be decent but a persistent focusing error under tungsten light plus poor bokeh prompted me to sell it in favour of this lens Build Quality and Handling This is the first thing that you notice when you take it out of the case this is definitely not a kit lens The construction feels very good the focus ring is tight with tactile clicks at the near and far focus limit even though the ring will turn past the limit you can feel when it hits On the D7000 the Sigma HSM focusing is fast accurate and silent Focus Accuracy A common complain about the Sigma 30mm is that many copies seem to back or front focus On my D7000 I do have a 8 AF Fine Tune value set for this lens although I have that same value for most lenses and suspect that it is my camera which is at fault With the fine tune value though the lens is dead on at all focus distances My Olympus copy seemed to be free from this issue Aperture Bokeh This is of course the reason why one would buy this lens While there are many other lenses in this range which are either cheaper sharper or both there is very little in this price range which gives you a sharp f 1 4 Below I have a sample shot of my son demonstrating this Taken with Nikon D7000 Sigma 30mm f 1 4 ISO 100 1 30s exposure 100 crop To give a better idea of what the bokeh of this lens looks like I have included three images of the same subject All three shots were done in aperture priority on the E 620 the first was at f 1 4 the second at f 2 8 and the third at f 5 6 Note the cluttered background the hall light and the picture frames on the wall seem to melt away with the lower apertures The bokeh does not have many hard edges which can at times create the double outline when shooting things like sticks or other thin contrasty objects Test shot at f 1 4 Test shot at f 2 8 Test shot at f 5 6 One thing to note if you are used to shooting with 35mm cameras or larger DSLRs is that the depth of field of Olympus 2x crop cameras is abot 2 stops less than an equivalent full frame Nikon DX is about 1 stop less DOF than full frame This can be good or bad depending on your shooting style Regardless I feel that it is important to show you about what you can expect when using this lens The following shot is of my daughter s homemade toy robot named Jungle Jungle is about 2 meters from the camera in this shot which is approximately

    Original URL path: http://digitalcave.ca/resources/photography/sigma3014.jsp (2014-10-09)
    Open archived version from archive

  • The Digital Cave - Sigma 50/1.4 (for 4/3) Review
    had to sell to finance this lens the Sigma handles this much better even busy sticks and grass are rendered very smoothly One example of the bokeh is below Of course it was a closeup and so has thinner DOF than normal portraits would but it was shot at f 4 0 Regardless you can see the smooth bokeh which is characteristic of this lens A more traditional portrait is included below This one was shot at f 2 8 as you can see from the scale I was a fair distance away Even here although the background is not blurred into oblivion you can still see a distinct separation between foreground and background If my shutter could go to 1 8000 of a second I probably could have gotten to f 1 4 Oh well maybe next time Sharpness An added benefit to this is the sharpness of this lens It is at least as sharp as my 14 54 and unless I am mistaken I think that it may even be a bit sharper although I have not shot any test charts in controlled situations to verify this that is at least my impression It is definitely sharper than the Sigma 30 at identical focal lengths At f 1 4 it is soft but not unusable especially for portraits It sharpens up quickly and is very good from f 2 0 on When shooting high contrast items it lacks a bit of contrast at f 1 4 but this also quickly improves Below are some test shots from different lenses In cases where the focal length differs I moved the camera to try to frame the subject in the same way to ensure that no upscaling would be required The tested lenses include the Sigma 50 Sigma 30 and Zuiko Digital 14 54 Mk I All shots were manually focused using a tripod and 10x live view to ensure consistency All shots are 100 crops As the next photos show both of these lenses are slightly soft and lacking contrast at f 1 4 However for portraits these are perfectly usable Sigma 50 f 1 4 Sigma 30 f 1 4 By f 2 0 they both have sharpened and increased contrast considerably but the 50mm has noticeably pulled ahead Sigma 50 f 2 0 Sigma 30 f 2 0 By the time we get to f 2 8 the closest to the 14 54 s max aperture rounding down to give the 14 54 the benefit of the doubt the Sigma has pulled far ahead Sigma 50 f 2 8 Olympus 14 54 54mm f 3 5 Sharpness and contrast seem to max out somewhere between f 4 0 and f 5 6 for portraits you probably wouldn t want to go higher than this anyway At this setting it seems to be pretty much the same as the Olympus 14 54 Sigma 50 f 5 6 Olympus 14 54 54mm f 5 6 Chromatic Aberrations Like

    Original URL path: http://digitalcave.ca/resources/photography/sigma5014.jsp (2014-10-09)
    Open archived version from archive

  • The Digital Cave - Sigma 50-150/2.8 (for Nikon) Review
    The finish is the same smooth slightly sparkly finish that I have on my 30 1 4 and the rubber focusing zoom rings feel just about the same as the focus ring on the 30 1 4 A very nice aspect of the lens is that it is both internally focusing most modern lenses do this and internally zooming most modern lenses do not do this This means the length does not change as you zoom and there is no extending barrel to pump air and moisture into the lens and camera bodies This is a huge plus as far as I am concerned while this lens is not weatherproof by any stretch of the imagination I am much more confident with it than I would be with a lens with extending barrel Handling this lens is a dream The balance on my D7000 seems just about right and the zoom focus rings are well separated and large enough to easily grab It does not have a tripod mount unlike the Tokina which may be a problem for some and I admit it would be nice in some situations however for the most part I plan on handholding this lens as it is going to be used mostly for portraits Focus Speed Accuracy As an HSM lens focus speed is good I have no complaints about it Focus accuracy seems to be OK indoors at night i e poor lighting although it is not perfect This is likely to be partially due to the D7000 as even with other lenses I have not had the best luck focusing indoors with Tungsten lighting Once I do some real world shots outside I will edit this review and give a better idea of how it handles After a fair bit of shooting I ended up with a 13 value for the AF fine tuning for this lens This is pretty consistent with the rest of my lenses on the D7000 I may have a camera that consistently back focuses but that is what the AF adjustment is for With this lens and 13 I find that focus is dead on from 60mm to 140mm at 50mm it backfocuses slightly and at 150mm it frontfocuses slightly Given my use of the lens almost exclusively portraits this works out fine I could probably adjust it to 15 or so and have a perfect 50mm but I prefer the mid ranges anyway when shooting portraiture I tend to think at 85mm on DX On the D7000 live view autofocus does not work This is a problem common to all Sigma lenses which I own including the 30 1 4 and 10 20 4 5 6 Sigma has an open offer to upgrade the firmware on these lenses free of charge I am planning on using this service eventually but for now I don t use live view enough to bother Image Quality No matter how nice a lens feels in the hand without good images

    Original URL path: http://digitalcave.ca/resources/photography/sigma5015028.jsp (2014-10-09)
    Open archived version from archive