tag:blogger.com,1999:blog-2599082310926453927.post5445430225329408029..comments2024-02-26T14:48:08.264+01:00Comments on Falk Lumo: LumoLabs: Shutter-induced blur with an SLR cameraFalk Lumohttp://www.blogger.com/profile/00476649880132648032noreply@blogger.comBlogger35125tag:blogger.com,1999:blog-2599082310926453927.post-64788950663763240092011-04-11T10:07:45.590+02:002011-04-11T10:07:45.590+02:00@stan: About K-x, I am sorry but I didn't cond...@stan: About K-x, I am sorry but I didn't conduct any tests about the issue with the K-x. I may have an opinion but I hate adding noise to the internet.<br /><br />About blur calculation: If you follow the advice in the abstract of the paper, right before the first section "1.Motivation" starts, then you'll find all information required, incl. the software used. I could just quote the link again but using the software alone is not giving good results.Falk Lumohttps://www.blogger.com/profile/00476649880132648032noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-7367080104229715092011-04-09T21:57:53.255+02:002011-04-09T21:57:53.255+02:00you probably use some program to calculate blur fr...you probably use some program to calculate blur from the image. Could you advice where to find such program? Thank'sUnknownhttps://www.blogger.com/profile/13101540676815415386noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-74192321007719461142011-04-09T21:45:45.465+02:002011-04-09T21:45:45.465+02:00Hi Falk,
I tested the shutter blur with two Pentax...Hi Falk,<br />I tested the shutter blur with two Pentax k-x bodies, both are affected by the issue. The shutter blur subjectively degradates image quality a lot at 100% zoom, it is really disturbing to me. It is difficult to me to compare my results with your measurements. I think you own also k-x. I know you made no exact tests with k-x. But you surely have at least some feeling how compares k-x & k-7 regarding shutter blur. It would be appreciated to make a note about it here. Thank'sUnknownhttps://www.blogger.com/profile/13101540676815415386noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-63229844409647720202011-03-15T23:20:02.597+01:002011-03-15T23:20:02.597+01:00Great study !, thank's for your big contributi...Great study !, thank's for your big contribution to resolve problems of many Pentaxians. I finally found the reason for part of my blurred pictures.Unknownhttps://www.blogger.com/profile/13101540676815415386noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-56965237886315697352010-12-02T20:04:28.027+01:002010-12-02T20:04:28.027+01:00What the findings of this research did to me (afte...What the findings of this research did to me (after coming from istDS, leaving out various generations of cameras that were way better then the DS on so many levels and finally picking up that brand new K7) was constantly and panicly looking at the shutterspeed when shooting (i ususally shoot with AV mode only). It's so irrational to look out for the shutterbug in such a way but i do it because i had a very small amount of winner shots destroy by slight blurring from the old DS days. And so it's becoming a real hassle - i constantly try to avoid anything from 1/50 up to 1/125 and even then taking multiple shots because of being paranoid. Certainly i pay tribute to my controlish character but it takes the fun out of it - otherwise i would totally love this camera and don't need anything else or better for my personal photography.<br /><br />Thanks for your work anyway and i mean it, otherwise we would be still wondering if it's a regular user error. I for myself can't feel so 100% loyal to pentax like a couple of years ago but i guess i will stay because my investment in lenses - got myself a truly great 12-24 a couple of months ago. And i just love going fully manual K or M with my old DS.<br /><br />But why o why can't Pentax come up with a primitive auto iso solution avoiding this speed region in a firmware - a maniac like me just wants a convenient workaround, i don't expect a fix or something. But i think the k7 is not in focus of Firmware Development anymore.<br />Hard days for true Pentaxians :(slashjacknoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-8388130594750155022010-10-23T12:19:41.323+02:002010-10-23T12:19:41.323+02:00I have the K-x and I have noticed this in some of ...I have the K-x and I have noticed this in some of the pictures, always blaming the SR. Of course, it does not bother me that much, since I had the trouble maybe with around 200 images out of 25 000.<br />Thank You very much for this research!stanichttp://www.pentaxforums.com/forums/members/stanic.htmlnoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-68241158571461039332010-09-01T21:50:48.234+02:002010-09-01T21:50:48.234+02:00Thanks so much for this report! I had this problem...Thanks so much for this report! I had this problem with two Pentax K-x and one K-7, but not with my older K20D. Unfortunately my history with Pentax is about to end due to this blurring issue. I don't dare buying another Pentax DSLR.<br /><br />/AnnaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-61077742623948600752010-08-11T01:04:41.355+02:002010-08-11T01:04:41.355+02:00GrJeck comment not passing minimum required qualit...GrJeck comment not passing minimum required quality for a comment.Falk Lumohttps://www.blogger.com/profile/00476649880132648032noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-45386137595089558882010-08-10T22:18:18.487+02:002010-08-10T22:18:18.487+02:00This comment has been removed by a blog administrator.GrJecknoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-46516463742457057802010-08-02T21:46:21.067+02:002010-08-02T21:46:21.067+02:00Hi,
On the dpr forum, regarding my blurry images, ...Hi,<br />On the dpr forum, regarding my blurry images, they always told me that it is "User Error" and it is obviously camera error. ThanksOZMikenoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-89143679995698941122010-07-31T12:25:10.493+02:002010-07-31T12:25:10.493+02:00Hi Falk,
Thanks very much for your hard research, ...Hi Falk,<br />Thanks very much for your hard research, I have noticed something amiss with my K7. I previously owned a K10D which was pin sharp, and now with my K7 I have noticed blur even when shooting at 1/125 - I thought it was perhaps the fact that a higher resolution sensor needs to be held steadier and more prown to show camera shake. The dpreview forum didn't think so.....but you have answered my query, thanks.<br />My question, do you think if I purchase a D-BG4 grip the extra mass & stability will reduce the shutter induced blur of the K7? On the other hand, I'm afraid to invest any further in this system.Stephan & Lindi Buschhttps://www.blogger.com/profile/12436819099105041665noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-44666731181880217742010-07-30T20:58:13.576+02:002010-07-30T20:58:13.576+02:00Witty F.A.Q. anyway...
Thanks for showing us the t...Witty F.A.Q. anyway...<br />Thanks for showing us the truth.Marcnoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-25704268462185584912010-07-30T01:36:54.020+02:002010-07-30T01:36:54.020+02:00Thank You Falk Lumo and crew...Thank You Falk Lumo and crew...Reallynoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-34799252535429947452010-07-28T11:41:49.062+02:002010-07-28T11:41:49.062+02:00@Derek, not everybody shares the same sense of hum...@Derek, not everybody shares the same sense of humour. To put a list of FAQ below an article when brand new is a "paradox" joke obviously, esp. if it includes questions which certainly have never been asked. Because at least one person did not get it, let me say that there are no further jokes. But believe me, the best scientific publications include the occasional joke.Falk Lumohttps://www.blogger.com/profile/00476649880132648032noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-33413839096424661002010-07-28T01:33:31.639+02:002010-07-28T01:33:31.639+02:00Reading the first eight Questions again and again ...Reading the first eight Questions again and again I fail to see anything humorous in them (the last two could be seen as mildly amusing). Possibly my engineering background blunted my sense of humor over the years :)<br />After your response one needs to wonder: was your intention to do serious testing and write a serious paper, or is it that some sections are a humorous joke? We already know that some parts are humorous, now, which ones? It is difficult to say, unless one replicates your testing and compares the results...<br />Nice talking to you, Derek.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-4203653221888090582010-07-27T12:17:03.846+02:002010-07-27T12:17:03.846+02:00@Derek,
please, refer to http://en.wikipedia.org/...@Derek,<br /><br />please, refer to http://en.wikipedia.org/wiki/Humour#Humour_formulaFalk Lumohttps://www.blogger.com/profile/00476649880132648032noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-50777281679774702692010-07-27T02:01:57.876+02:002010-07-27T02:01:57.876+02:00Falk, publishing a paper which immediately include...Falk, publishing a paper which immediately includes a series of Frequently Asked Questions is illogical self referencing. By definition there can not be FAQ-s on 'day zero'. They are questions you created in your mind, not questions ASKED by the readers, and not FREQUENTLY. There were no readers yet when you released the paper (and please, do not say that many people read your paper before you published it, and you collected their questions as FAQ instead of folding the questions into the paper before the release).<br /><br />Do you mean something like: questions nobody asked, but some intellectually disadvantaged or not careful readers could possibly ask them, so before anyone asks, I will pretend many already did, and answer them here anticipating they will come? Hmmm...<br /><br />Regards, DerekAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-68985789736903736822010-07-25T18:52:16.750+02:002010-07-25T18:52:16.750+02:00@Elmar: well, we did a full PD controller simulati...@Elmar: well, we did a full PD controller simulation taking all this into account. There is no "null point", just weaker forces for weaker deviations. Ut to Fmax for large deviations.<br /><br />Ignore SR, automatic horizon correction and everything. This just influences some "goal" position which is to be considered a constant during the entire shutter event. You are mixing two different time scales here.Falk Lumohttps://www.blogger.com/profile/00476649880132648032noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-3221377815703773142010-07-25T12:43:23.521+02:002010-07-25T12:43:23.521+02:00Falk, Fmax would be applicable when driven hard, b...Falk, Fmax would be applicable when driven hard, but how much centreing effect is there really a few uM each side of the null? Or in other terms, how broad in uM is the null point?<br />I expect that it is not a brick wall ;) <br />We also have an additional bit of circuitry tacked on with the K7 over the K20 - the automatic horizon correction.<br />Perhaps this extra add-on has de-tuned the SR controller?<br />I believe that Pentax have been fiddling around with this SR controller, as I noticed that with FW17 horizons were no longer as level as I saw in the viewfinder. It's almost as if the sensor rotation factory calibration was being ignored. With FW22 it seems to be back to normal.<br />Just out of interest did you make any test shots with and without horizon correction? Was there any difference?Elmarnoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-90304506218310715792010-07-25T11:45:22.958+02:002010-07-25T11:45:22.958+02:00@Elmar: you make an interesting proposition. In th...@Elmar: you make an interesting proposition. In the study's language, this would amount to increasing the maximum magnetic driving force called Fmax (below Fig.22). Not a bad idea.<br /><br />However, the study suggests that Fmax is sufficient. Our simulation includes the "leap into position from the resting spot at the bottom of the mirror box" as you say. This happens within a rather short period of time (18ms if I remember correctly) and our simulation delivers a minimum value for Fmax where this can succeed (driving and lock the sensor position). Using this minimum value Fmax, our simulation shows that it does also suffice to withstand the shock from the shutter-induced accelerations well enough. If the controller loop is as well behaved as the one in our simulation.<br /><br />This is why we believe that it isn't a principle flaw of the SR mechanism but just an oversight for a yet to be identified detail. The fact that the K20D works well enough further supports our believe that the magnetic strength Fmax isn't simply too weak. But if, the idea may help; if feasible w/o physically changes to the camera.Falk Lumohttps://www.blogger.com/profile/00476649880132648032noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-48583944247420131112010-07-25T04:22:01.225+02:002010-07-25T04:22:01.225+02:00Falk, The magnetic actuators that hold the sensor ...Falk, The magnetic actuators that hold the sensor in position seem to be pairs of coils working in opposition to each other working on a rare earth permanent magnet. These are positioned on all 4 sides of the sensor's floating plate. The balance of current and hence flux between the opposed coils gives a null point where the sensor sits once it has leapt into position from it's resting spot at the bottom of the mirror box. These null points have been made accessible to us K7 users during live view, where we can trim the sensor position, presumably by reducing current in one coil and increasing it in the other. Perhaps if the base current through both coils could be increased somewhat (without burning out the coils or using too much battery capacity) the sensor may be held firmer in position and be able to resist the shock from the shutter. This may be only possible to implement with SR off, as it may effect the range of sensor movement with SR on. I could live with SR off at 1/80s with my 15mm lens and have the sensor held more securely!Elmarnoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-8496992698920026262010-07-24T11:26:25.419+02:002010-07-24T11:26:25.419+02:00@dosdan: yes, if the control is done by the CPU as...@dosdan: yes, if the control is done by the CPU as described in the patent. However, firmware symbols hint at an IC chip doing this and then it may or may not be possible without replacing this chip. Depending on the exact function of the chip. But sloppy control parameters are just ONE possibility to explain the measurements.<br /><br />But yes, there is a scenario where a firmware update could help. It's likelihood is another story.Falk Lumohttps://www.blogger.com/profile/00476649880132648032noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-16046520610088970932010-07-24T00:20:52.878+02:002010-07-24T00:20:52.878+02:00In your white paper conclusion you've stated:
...In your white paper conclusion you've stated:<br /><br />A sloppy, unstable, weak, ill behaving non-linear image sensor position controller magnifies the effect (for selected shutter speeds between about 1/180 s to 1/60 s) by another 100 %. <br /><br />Is it possible for this loop behaviour to be tighened up via a firmware upgrade?<br /><br />Dosdan.dosdanhttps://www.blogger.com/profile/09028483494728032681noreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-10946020057686906202010-07-23T16:11:19.602+02:002010-07-23T16:11:19.602+02:00Thank You that You provided a solution for better ...Thank You that You provided a solution for better photographs with our gear.<br />All the best for You guys.<br />Ivan.Ivannoreply@blogger.comtag:blogger.com,1999:blog-2599082310926453927.post-29830512062830804912010-07-23T05:20:06.460+02:002010-07-23T05:20:06.460+02:00Falk, your FAQ is funny! Nice~
I don't ask yo...Falk, your FAQ is funny! Nice~<br /><br />I don't ask you any question as I have not fully digested/understood your test and report. As such, I dare not to ask you anything! ;-)RiceHighhttps://www.blogger.com/profile/12174156471696420785noreply@blogger.com