Hi, just wanted to say that I'm currently studying for my exams which include lenses and optical aberrations, and this video was amazing in explaining it. Loved the clear and well worded explanations, keep up the good work! :)
Your channel channel inspired me to take up optical systems course. It is so fun to learn, also the book by Eugene Hecht on this topic is so well written! I do find a few inconsistencies in this video though.
I was shooting the milky way this weekend and I tried to use the 50mm NIKON 1.8 that I had when I originally bough the camera. I tried to do a longer exposure of about 69 seconds with a tracker, this was the first time I tried to use this lenses for it, because I usually use my Rokinon 14mm 2.8 as I tend to like the wide angle shots. But I notice the coma in the light of the stars as you mentioned in the beginning of the video, as it is a cheap lens, I will try to change the aperture and see how it will look like. Wanted to tell you that I really like your videos because photograph is also the geekiness of getting to explore optics and astronomy, to me just includes all my favorite things. Please keep doing those videos I really find them very helpful and informative. And I am sorry English is not my native language.
What's the exact difference between spherical and petzval aberration. They're not the same thing? Would you use an aspherical element to correct for petzval? This is the best lecture I've heard on this. I'm experimenting with trying to kitbash my own lenses and having a lot of fun but everything I put together always has one or the other distortions to it. Interesting that I probably need some aspherical elements to fix it.
They are different. Spherical aberration causes parallel lines to focus at different distances based on how far away from the center of the lens they are. Not all the rays from different parts of the lens will focus to the same point. Petzval distortion makes like focus to a spherical projection, rather than a flat plane. This is also called field curvature. Do an image search for "spherical aberration" and "field curvature" to see the light ray diagrams for more clarification. Petzval is hard to correct, but can be helped by using smaller apertures. Aspherical elements correct spherical aberration.
I've watched all your videos from the first post on this channel to the current one. Your explanations of optics are superb. So far you've given a good theoretical explanation on what's going on with the light and the lenses. Really cool stuff. I plan on messing around with some old-school cameras pretty soon. I've been wanting to get my hands wet with silver-based type photography, but I have no camera yet. I don't know if I should buy one, build one, ..., etc. Those 'Zero Image' pinhole camera from China look really cool, but I like the idea of being able to fit a lens easily should I choose to do so. I don't want to become a master know-everything-about-everything photographer, but I do want to become familiar enough with silver-based photography in order to be able to take good clear images, hopefully Daguerreotypes one day, and to develop some general chemistry labs (I'm a chem instructor) that deal with the redox chemistry that's occurring.
Best of luck in your quest, down the rabbit hole you go! 35mm SLRs are very affordable and the film is readily available. If you want something that's even more simple look into the Holga which is a medium format camera. The possibilities are endless. Thanks for watching and stay tuned for more videos. In about a month I'll be talking about the film process!
Great video! I am an Optometry student and this helped greatly, It probably wasn't as in-depth as I need but it was a great platform for me to understand the basics and build from there. From me and every other optometry student, I thank you for making this video.
3:00 totally wrong, the rays coming in through the centre of the lens correspond to a smaller aperture, NOT the centre of the sensor. Spherical aberration has nothing to do with corner versus centre sharpness. A lens with spherical aberration will be blurry throughout. 9:17 wrong again, that’s simply impossible unless your lens isn’t spherically symmetrical. 11:00 field curvature is NOT swirly broken... And no it’s not eliminated at all, most modern lenses have visible field curvature.
@@TheScienceofPhotography I suggest you point to specific spots where it shows I'm supposedly wrong. I think the worst part is how ever 2 years you haven't improved one bit in your understanding.
With respect to both of you. 3.00 - while chen gong is right that it’s not a good generalisation, most of the analysis of spherical aberration is done with objects at infinite distance, like a star. Basically it would cause airy discs around the star. 9.17 chen gong is right. Astigmatism is a bit more complex thing and I’m still trying to wrap my mind around it. When you think about astigmatism, you should think about objects not on optic axis. Now you can quite easily see that they don’t converge at same point. Tele photo lenses don’t have much field curvature I guess. Only the wide angle ones show appreciable level of field curvature (and of course wide aperture ones)
I'm not a photographer, I'm actually an optometry student, and your videos are super helpful for visualising! Thank you very much.
Glad I could help! Thanks for stopping by!
Hi, just wanted to say that I'm currently studying for my exams which include lenses and optical aberrations, and this video was amazing in explaining it. Loved the clear and well worded explanations, keep up the good work! :)
You are very welcome. I am glad it helped. Good luck on your exams!
So nice❤
Thank you very much
I am student of optic ❤
ME student saying thanku!
I was studying lens abberations for spectrometry courses, this video helped. Thankyou
Your channel channel inspired me to take up optical systems course. It is so fun to learn, also the book by Eugene Hecht on this topic is so well written!
I do find a few inconsistencies in this video though.
Excellent description !! I always need good illustrations to understand phenomena - yours are really helpful ! 👍👍👍 Thank you ! 🙏🙏🙏
Very nice presentation. Well explained and more scientific than commercial.bla bla bla.
Not a photographer, biology student is here, trying to learn about microscopy. Tnx
I was shooting the milky way this weekend and I tried to use the 50mm NIKON 1.8 that I had when I originally bough the camera. I tried to do a longer exposure of about 69 seconds with a tracker, this was the first time I tried to use this lenses for it, because I usually use my Rokinon 14mm 2.8 as I tend to like the wide angle shots. But I notice the coma in the light of the stars as you mentioned in the beginning of the video, as it is a cheap lens, I will try to change the aperture and see how it will look like. Wanted to tell you that I really like your videos because photograph is also the geekiness of getting to explore optics and astronomy, to me just includes all my favorite things. Please keep doing those videos I really find them very helpful and informative. And I am sorry English is not my native language.
Great stuff! I do not understand why the oblique light causes coma?
Sensor curvature may resolve not just field curvature, but also diffraction in small aperture values. Nikon already filed a patent.
Interesting. Thank you for sharing.
Thank you❤💓
Another excellent video , would it be possible to have a video giving an insight into Diffraction ? , many thanks
nice explanation.
shaamsul Arefin Thanks!
What's the exact difference between spherical and petzval aberration. They're not the same thing? Would you use an aspherical element to correct for petzval? This is the best lecture I've heard on this. I'm experimenting with trying to kitbash my own lenses and having a lot of fun but everything I put together always has one or the other distortions to it. Interesting that I probably need some aspherical elements to fix it.
They are different. Spherical aberration causes parallel lines to focus at different distances based on how far away from the center of the lens they are. Not all the rays from different parts of the lens will focus to the same point. Petzval distortion makes like focus to a spherical projection, rather than a flat plane. This is also called field curvature. Do an image search for "spherical aberration" and "field curvature" to see the light ray diagrams for more clarification.
Petzval is hard to correct, but can be helped by using smaller apertures. Aspherical elements correct spherical aberration.
Many thanks for the videos.
exceptional 3d ray diagrams
Excellent and very educative video. The only thing that can make it better are some sample pictures of the aberrations. Congratulations and good job!
Thank you. Also, that is a really good idea for a follow up video!
Excelent video
Subbed
Great channel, good in-depth information well explained.
Thank you very much!
I cannot find your video about the Petzval lens. can you please link it to me?
Great explanation! I'd recommend including photo examples.
Master of optics 👍
Thanks!
I've watched all your videos from the first post on this channel to the current one. Your explanations of optics are superb. So far you've given a good theoretical explanation on what's going on with the light and the lenses. Really cool stuff. I plan on messing around with some old-school cameras pretty soon. I've been wanting to get my hands wet with silver-based type photography, but I have no camera yet. I don't know if I should buy one, build one, ..., etc. Those 'Zero Image' pinhole camera from China look really cool, but I like the idea of being able to fit a lens easily should I choose to do so. I don't want to become a master know-everything-about-everything photographer, but I do want to become familiar enough with silver-based photography in order to be able to take good clear images, hopefully Daguerreotypes one day, and to develop some general chemistry labs (I'm a chem instructor) that deal with the redox chemistry that's occurring.
Best of luck in your quest, down the rabbit hole you go!
35mm SLRs are very affordable and the film is readily available.
If you want something that's even more simple look into the Holga which is a medium format camera.
The possibilities are endless.
Thanks for watching and stay tuned for more videos. In about a month I'll be talking about the film process!
thanks! that was very useful
very helpful video
Great video! I am an Optometry student and this helped greatly, It probably wasn't as in-depth as I need but it was a great platform for me to understand the basics and build from there. From me and every other optometry student, I thank you for making this video.
Same!! it's always amusing to see how optometry is closely connected to the lens and camera, astronomy!
Outstanding video. Would it be possible to ask you a few hypothetical questions
Go ahead, I'll do my best to answer
Obviously stitch the rotated photos together
very informative, thank you!
You're welcome!
You're a life-saver!
I'm glad this video was able to help!
3:00 totally wrong, the rays coming in through the centre of the lens correspond to a smaller aperture, NOT the centre of the sensor.
Spherical aberration has nothing to do with corner versus centre sharpness. A lens with spherical aberration will be blurry throughout.
9:17 wrong again, that’s simply impossible unless your lens isn’t spherically symmetrical.
11:00 field curvature is NOT swirly broken...
And no it’s not eliminated at all, most modern lenses have visible field curvature.
I suggest you read through this page and its associated links and then delete your comment: en.wikipedia.org/wiki/Optical_aberration
@@TheScienceofPhotography I suggest you point to specific spots where it shows I'm supposedly wrong.
I think the worst part is how ever 2 years you haven't improved one bit in your understanding.
With respect to both of you.
3.00 - while chen gong is right that it’s not a good generalisation, most of the analysis of spherical aberration is done with objects at infinite distance, like a star. Basically it would cause airy discs around the star.
9.17 chen gong is right. Astigmatism is a bit more complex thing and I’m still trying to wrap my mind around it. When you think about astigmatism, you should think about objects not on optic axis. Now you can quite easily see that they don’t converge at same point.
Tele photo lenses don’t have much field curvature I guess. Only the wide angle ones show appreciable level of field curvature (and of course wide aperture ones)