The 2nd image is with digital and optical zoom in play along with theDCR250
dick
Hey Rik,,,,,,,,,
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Hey Rik,,,,,,,,,
Now I have a pic of a scale too,whats it telling me?It is also a DCR250 on a fixed lens.Just like the camera saw it, no PP what so ever,27mm wide.
The 2nd image is with digital and optical zoom in play along with theDCR250
dick
The 2nd image is with digital and optical zoom in play along with theDCR250
dick
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rjlittlefield
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First off, let me compliment you on the clarity of these images. The images look sharp side to side in the plane of focus and I don't see any trace of CA (chromatic aberration = colored fringes). This indicates that your optics are working well.
Now, regarding the second image as compared to the first...
I'm not sure what you mean by "digital and optical zoom in play".
Obviously the second image is seeing a wider area, more like 33 mm.
That could be a result of zooming wider, and zooming wider is the usual approach toward getting a wider field.
It could also be an unexpected side effect of focusing closer at the same zoom setting. That one's hard to understand, but basically it happens because some lenses focus closer by shortening their focal length. When used by themselves, those lenses behave sanely because focusing closer usually means moving closer, which makes the field smaller as you'd expect. But when used in conjunction with a strong second lens, the reduced focal length has more effect than moving a little closer does. The overall result is that the field gets bigger, not smaller as you'd expect.
The simple situation to understand is when the camera is focused at infinity. In that case, the magnification onto sensor is just proportional to the focal length of the camera lens, so zooming in and out produces intuitive results.
I don't have a camera like yours to test with, so I can't say how the various zooms and focus interact when used with the Raynox. You'll have to experiment yourself. Be sure to carefully check your settings and take notes, and be prepared to repeat the experiments as you acquire more experience and realize that previous results "don't seem right". Sometimes discrepancies are due to lack of understanding, and sometimes the actual camera settings were different from the notes. (How do I know this, you ask? Don't ask.
)
--Rik
Now, regarding the second image as compared to the first...
I'm not sure what you mean by "digital and optical zoom in play".
Obviously the second image is seeing a wider area, more like 33 mm.
That could be a result of zooming wider, and zooming wider is the usual approach toward getting a wider field.
It could also be an unexpected side effect of focusing closer at the same zoom setting. That one's hard to understand, but basically it happens because some lenses focus closer by shortening their focal length. When used by themselves, those lenses behave sanely because focusing closer usually means moving closer, which makes the field smaller as you'd expect. But when used in conjunction with a strong second lens, the reduced focal length has more effect than moving a little closer does. The overall result is that the field gets bigger, not smaller as you'd expect.
The simple situation to understand is when the camera is focused at infinity. In that case, the magnification onto sensor is just proportional to the focal length of the camera lens, so zooming in and out produces intuitive results.
I don't have a camera like yours to test with, so I can't say how the various zooms and focus interact when used with the Raynox. You'll have to experiment yourself. Be sure to carefully check your settings and take notes, and be prepared to repeat the experiments as you acquire more experience and realize that previous results "don't seem right". Sometimes discrepancies are due to lack of understanding, and sometimes the actual camera settings were different from the notes. (How do I know this, you ask? Don't ask.
)--Rik
I did a bit of looking and here's a link that may explain the optical/digital zoom,looks to me like I need to shut it off and do the cropping later,don't know what the advantage might be.need to read further
http://www.photoxels.com/digital-photog ... ital-zoom/
Thanks for the KUDO on clarity but ,How's the old saying go? A blind hog finds an acorn every now and then
dick
http://www.photoxels.com/digital-photog ... ital-zoom/
Thanks for the KUDO on clarity but ,How's the old saying go? A blind hog finds an acorn every now and then
dick
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rjlittlefield
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Right, digital zoom serves no purpose here.
But optical zoom is your friend. As Charles Krebs pointed out HERE*, with a 3S IS camera at full optical zoom (12X) and a Raynox 250 on front you should be getting about 10 mm wide, not the 27 mm you've shown here. I'm wondering if the image shown here had the 3S IS set on something more like 5X optical zoom.
Try it again with the 3S IS set on maximum optical zoom, no digital zoom, camera focused at infinity. I'll be interested to see how close the prediction matches the experiment.
--Rik
* Charles expresses the field width in inches, 0.44 x 0.33, perhaps calculated from the spec of "432 mm equiv". I do the calculation in mm using the sensor width of 5.744 mm and the actual FL of 72 mm, combined with the Raynox FL of 125 mm (8 diopters). Actual magnification will be 72/125, field width 5.744/magnification = 9.97 mm. Either way, around 10.
But optical zoom is your friend. As Charles Krebs pointed out HERE*, with a 3S IS camera at full optical zoom (12X) and a Raynox 250 on front you should be getting about 10 mm wide, not the 27 mm you've shown here. I'm wondering if the image shown here had the 3S IS set on something more like 5X optical zoom.
Try it again with the 3S IS set on maximum optical zoom, no digital zoom, camera focused at infinity. I'll be interested to see how close the prediction matches the experiment.
--Rik
* Charles expresses the field width in inches, 0.44 x 0.33, perhaps calculated from the spec of "432 mm equiv". I do the calculation in mm using the sensor width of 5.744 mm and the actual FL of 72 mm, combined with the Raynox FL of 125 mm (8 diopters). Actual magnification will be 72/125, field width 5.744/magnification = 9.97 mm. Either way, around 10.
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rjlittlefield
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I believe you're using a Canon S3 IS. That camera has a manual focus mode (page 66 of the Advanced Users Guide). Put the camera in manual focus. Remove the Raynox, point the camera out the window, and focus it on something far away like the horizon. That's infinity focus. Remember what that looks like in terms of the camera's indicators and what buttons you pushed to get there. Now do not touch the camera's focus control again. Put the Raynox back on and take another shot of the scale and nickel, adjusting focus only by changing the camera-to-subject distance.
--Rik
--Rik
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rjlittlefield
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Dick, these images are confusing me something awful. The first image you showed had a 27 mm field. The second one, "with digital and optical zoom in play" was 33 mm. And this last one, which I thought I had asked to be on maximum optical zoom, is 44 mm. But the calculation says it should have been around 10 mm. These calculations are generally quite reliable, so I'm thinking that either you don't have the hardware I think you do, or it's not getting set the way I intended.
Here's an example I just ran, showing a Raynox 250 stuck on the end of a "320 mm equivalent" lens on a different type of camera. Calculation says it ought to be about 14 mm field width; measurement says it's about 13.7.
So let's try this again.
1. Do you have a Canon S3 IS?
2. Does it say on the front of the camera lens, 6.0 - 72.0 mm?
3. Do you have a Raynox Model M-250 lens?
4. Do you have the camera set to maximum optical zoom? (See page 41 of the Advanced Camera User Guide: press the "tree" end of the zoom button and hold it until the zoom stops changing.)
The reason I'm asking these questions is because you've expressed an interest in photographing as small as you can with good quality, and I'm trying to help you use the Raynox to do that. If this becomes bothersome, let me know and I'll go do other stuff.
--Rik
Here's an example I just ran, showing a Raynox 250 stuck on the end of a "320 mm equivalent" lens on a different type of camera. Calculation says it ought to be about 14 mm field width; measurement says it's about 13.7.
So let's try this again.
1. Do you have a Canon S3 IS?
2. Does it say on the front of the camera lens, 6.0 - 72.0 mm?
3. Do you have a Raynox Model M-250 lens?
4. Do you have the camera set to maximum optical zoom? (See page 41 of the Advanced Camera User Guide: press the "tree" end of the zoom button and hold it until the zoom stops changing.)
The reason I'm asking these questions is because you've expressed an interest in photographing as small as you can with good quality, and I'm trying to help you use the Raynox to do that. If this becomes bothersome, let me know and I'll go do other stuff.
--Rik
Rik I appreciate you spending the time to mget me on the right road,my error
#1 thru #3 is YES
#4 is NO I dropped the ball ,on that one.
Here's a retake at full OZ,I didn't bother with the flash but it looks like 11 is the number as you calc'ed it should be,what next coach,
dick
I went back and got a closer look at the nickel also.This is really helpful.This also was in the range of 4 to 5 inches working room,which I think is good.
#1 thru #3 is YES
#4 is NO I dropped the ball ,on that one.
Here's a retake at full OZ,I didn't bother with the flash but it looks like 11 is the number as you calc'ed it should be,what next coach,
dick
I went back and got a closer look at the nickel also.This is really helpful.This also was in the range of 4 to 5 inches working room,which I think is good.
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rjlittlefield
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Yes!!!
The optics are now working as expected. I'm seeing a bit of chromatic aberration in this, but it's not too bad and it looks to be fixable using Photoshop's Filter > Lens Correction > Custom and moving the slider for "Fix Red/Cyan Fringe".
Refresh my memory, please -- what do you have for image processing software?
For shooting pictures of small stuff using a closeup lens (the Raynox), the trick is to stop down your camera lens a long ways, perhaps as far as it will go. That will give you the greatest depth of field without blurring the image too much from diffraction. If you see warnings elsewhere about the perils of stopping down too far, ignore those. The rules are different when you're using a closeup lens versus extending a lens on bellows or tubes. It has to do with "effective f-number", which with a closeup lens is equal to the camera's setting but with bellows or tubes is some multiple of the lens setting.
The next trick is figuring out how to get enough light onto your subject, properly diffused so as to avoid too-bright highlights and too-dark shadows.
Once you have those two mastered, then the challenges become things like composition (on the one hand) and focus stacking for more DOF (on the other). Again, both aspects can keep you occupied for a long time.
Anyway, I think you're off to the races now. Pick a subject, see what you can do with it, and ask for feedback!
Best regards,
--Rik
The optics are now working as expected. I'm seeing a bit of chromatic aberration in this, but it's not too bad and it looks to be fixable using Photoshop's Filter > Lens Correction > Custom and moving the slider for "Fix Red/Cyan Fringe".
Refresh my memory, please -- what do you have for image processing software?
Well, uh, there's not any particular "next" from here. You know now how to set the camera to focus on small stuff -- at least down to 11 mm field width. I assure you, things will be plenty difficult enough at that scale to keep you practicing for a while.what next coach,
For shooting pictures of small stuff using a closeup lens (the Raynox), the trick is to stop down your camera lens a long ways, perhaps as far as it will go. That will give you the greatest depth of field without blurring the image too much from diffraction. If you see warnings elsewhere about the perils of stopping down too far, ignore those. The rules are different when you're using a closeup lens versus extending a lens on bellows or tubes. It has to do with "effective f-number", which with a closeup lens is equal to the camera's setting but with bellows or tubes is some multiple of the lens setting.
The next trick is figuring out how to get enough light onto your subject, properly diffused so as to avoid too-bright highlights and too-dark shadows.
Once you have those two mastered, then the challenges become things like composition (on the one hand) and focus stacking for more DOF (on the other). Again, both aspects can keep you occupied for a long time.
Anyway, I think you're off to the races now. Pick a subject, see what you can do with it, and ask for feedback!
Best regards,
--Rik