tag:blogger.com,1999:blog-1219947499730924418.post3505662087538460785..comments2023-06-10T03:06:05.447-07:00Comments on cinetinker: RX vs non-RX lensesdomhttp://www.blogger.com/profile/08759191212624785810noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-1219947499730924418.post-55177334255721648342020-11-01T21:14:34.850-08:002020-11-01T21:14:34.850-08:00Hello,
Do you have any experience dismantling the...Hello,<br /><br />Do you have any experience dismantling the Beaulieu optivaron lens ?., mine has a bent joint just after the iris and I cant remove it.<br /><br />FredTurtle Mythhttps://www.blogger.com/profile/01573320621817242421noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-51152171982473705172019-10-14T08:50:19.679-07:002019-10-14T08:50:19.679-07:00Thank you for your clear explanation. I misunderst...Thank you for your clear explanation. I misunderstood the purpose of the lens comparaison test.<br /><br />Bolexstasehttps://www.blogger.com/profile/09844341824352833769noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-71371526497551044092019-10-14T08:49:55.234-07:002019-10-14T08:49:55.234-07:00This comment has been removed by the author.Bolexstasehttps://www.blogger.com/profile/09844341824352833769noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-11958415644956525332019-10-14T05:33:08.814-07:002019-10-14T05:33:08.814-07:00The tests were attempting to show the effects of u...The tests were attempting to show the effects of using RX lenses on cameras without a prism, and to give some indication of the difference between RX and non-RX lenses. I do have a projector with a glass plug now, but didn’t have one when I documented these tests. To accurately gauge the effects of stopping down a non-RX lens on a reflex Bolex, yes a glass plug in the projector path would be the best way.domhttps://www.blogger.com/profile/08759191212624785810noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-85820299095338208872019-10-14T01:53:54.748-07:002019-10-14T01:53:54.748-07:00Did you use the special glass in-between the lens ...Did you use the special glass in-between the lens and light source for your projection test? In order to test the RX lens properly you need to add a piece of glass that mimic the prism in between the projection light and lens. If you did not use such glass, you test is incorrect.<br /><br />This is the projection lens projector that Paillard use to work with:<br />https://ibb.co/WBNKhFc<br /><br />This is the piece of glass you have to add to your lens projector in order to test the RX Lenses:<br />https://ibb.co/TBPBx4K<br /><br />Greetings from SwitzerlandBolexstasehttps://www.blogger.com/profile/09844341824352833769noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-16175591142467598582019-02-17T11:10:21.105-08:002019-02-17T11:10:21.105-08:00Further reading on the subject (the Dennis Couzin ...Further reading on the subject (the Dennis Couzin documents you linked to) answered my first question: NO , I may not trust what I see on the ground glass though the reflex viewfinder , because "the Bolex prism stands not only between the lens and the film, but also between the lens and the groundglass."<br /><br />Ok. So then what about focusing through the Bolex Prismatic Focusing device ? That is mounted to the inside of the film gate, behind the prism, so what I see through the Prismatic Focuser should be accurate , right? If I am able to focus a non-RX C-mount lens and the focus setting made by this method agrees with double-checking the distance with a tape measure , then it would probably mean that the non-RX lens being tested is usable without fear of too much aberration , as long as the Rule of "stopped down to f/2.8 or more" is followed. (I notice Couzin says "f/2 or f/2.8" in his 1987 paper , but in his earlier 1976 paper he says "stopped down to f/3.2 or more".) <br /><br /><br />And still that exit pupil estimation test ... In his revised 1976 article Couzin says "If the pupil <i>*appears*</i> deep set in the lens, an inch or more back from the mount, then the lens passes." But then in the 1987 article says: "if the lens has a deep set exit pupil, about 1.5 inches or father into its screw mount". And your estimate: "an exit pupil distance of more than about 50mm [almost 2" inches] from the film plane should be fine stopped down to f/2.8 and beyond".<br /><br />So it's about 1" inch ... or 1.5" inch ... or is it 2"inches ... ? Couzin says "1 - 1.5" or more from the screw mount , but I think you're adding a half inch to your estimate, so the exit pupil distance is estimated as 2" inches or more <i>from the film plane</i>, is that right ? <br /><br /><br />Fritjof https://www.blogger.com/profile/12088044459124016061noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-17546728859918439602019-02-14T06:56:50.784-08:002019-02-14T06:56:50.784-08:00Good article, thank you for helping to clear up a ...Good article, thank you for helping to clear up a lot of the misinformation.<br /><br />QUESTIONS: one thing I'm still not clear on is why can't we trust what we see through the viewfinder with a non-RX lens mounted on the Bolex RX camera ? What I mean is , I've always been told that what I see on the ground glass is what I’ll get on film, in terms of the focus and depth-of-field. So, if a non-RX lens is going to have problems focusing I would expect to be able to see that the lens is out of focus , however if the focus looks sharp in the viewfinder at all distances from the closest setting to infinity should I not trust what I'm seeing on the ground glass ... does the aberration only become apparent when viewed on the processed film later ? <br /><br />Also this: would it help to test the suitability of a non-RX lens by using the Bolex Prismatic Focuser device which is inserted into the film gate and allows focusing at the film plane through the taking lens ? So if I mount a non-RX lens on the Bolex RX camera if it appears to be sharp and free of aberrations through the Prismatic Focuser , will it be in focus on the film ? Fritjof https://www.blogger.com/profile/12088044459124016061noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-58705464113199766462017-04-23T03:49:40.378-07:002017-04-23T03:49:40.378-07:00Great read! And very true sum up as I optically co...Great read! And very true sum up as I optically compared ar and rx on m43 myself to the same conclusions.hellrazorhttps://www.blogger.com/profile/01752866807196894161noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-78278630347459366352016-04-09T01:44:47.992-07:002016-04-09T01:44:47.992-07:00Wonderful contribution and tests, great to finally...Wonderful contribution and tests, great to finally see the difference!<br /><br />Thanks do much!!Dr Klaus Schmitthttps://www.blogger.com/profile/03292267493192344782noreply@blogger.comtag:blogger.com,1999:blog-1219947499730924418.post-79641559873261406072015-02-26T15:02:02.310-08:002015-02-26T15:02:02.310-08:00A wonderful article with the simplified and added ...A wonderful article with the simplified and added info.<br />Many thanks Dom!<br />Erkanprofessorhttps://www.blogger.com/profile/11693874221643155853noreply@blogger.com