Set up Questions

[thartl]

I have been using my canon 5dmkii with 3 kenko tubes (12mm, 20mm, and I think 36mm,) a canon 135mm with a reversed canon 50mm. Its been producing decent images - a tad soft.

My reversing ring finally arrived that allows me to reverse my 50mm on my bellows. What I found was disheartening. I have just as much magnification with the other set-up but a little less dof and a little harder to focus, and more vignetting.

Also, I noticed that the magnification doesn't change with the reversed 50mm when the bellows are fully extended (at least not alot.)

One of things I was really excited for with the reversing ring, is that my 50mm has a built in lens hood, so if the lens is mounted normal, and used with bellows, the subject has to be inside the hood and there is not really anway to light it. With a reversed lens I eliminate that problem. But it isn't giving me the magnification I want nor the clarity.

Any suggestions?

[rjlittlefield]

From your description, I'm wondering if what you have set up is what I'm imagining.

The setup with bellows should be camera + bellows + reversing ring + reversed lens, with no other components.

Using this setup with a 50 mm lens, you should get magnifications ranging from roughly 1X to something over 3X, depending on bellows length, and you should get no vignetting at any setting.

That fact that you're getting vignetting suggests to me that you have things fitted together differently, but I can't figure out how.

--Rik

[Harold Gough]

the subject has to be inside the hood and there is not really anway to light it.

Because of such short working distances bellows lenses giving the highest magnifications ranges are not provided with hoods. Even specialised macro lighting may not work in in extreme cases:The more bulky T8 ring flash (as opposed to the T10) works with my Zuiko 38mm lens but is not recommended with the 20mm

http://www.alanwood.net/photography/oly ... 38-28.html

http://www.alanwood.net/photography/oly ... -20-2.html

Harold

[thartl]

From your description, I'm wondering if what you have set up is what I'm imagining.

The setup with bellows should be camera + bellows + reversing ring + reversed lens, with no other components.

Using this setup with a 50 mm lens, you should get magnifications ranging from roughly 1X to something over 3X, depending on bellows length, and you should get no vignetting at any setting.

That fact that you're getting vignetting suggests to me that you have things fitted together differently, but I can't figure out how.

--Rik

I have the Camera then extension tube, then bellows, then ring, then reversed lens. No other components. The only difference is where the tube is, would that make the difference, I only put it between camera and bellows so the bellows fits better - the potruding parts of the camera body you know.

I put the reversing ring on my extension tubes, and no vignetting. I don't understand fully.

[thartl]

the subject has to be inside the hood and there is not really anway to light it.

Because of such short working distances bellows lenses giving the highest magnifications ranges are not provided with hoods. Even specialised macro lighting may not work in in extreme cases:The more bulky T8 ring flash (as opposed to the T10) works with my Zuiko 38mm lens but is not recommended with the 20mm

http://www.alanwood.net/photography/oly ... 38-28.html

http://www.alanwood.net/photography/oly ... -20-2.html

Harold

Thanks for the links although I am not sure I follow.

There is nothing I can do about the hood - they call it a hood but really all it is is the glass is recessed into the lens front about 1.5 inches. Thats why I want to reverse.

[Harold Gough]

they call it a hood but really all it is is the glass is recessed into the lens front about 1.5 inches. Thats why I want to reverse.

I have come across this misleading terminology recently but cannot recall where. I have the same recess problem with my newly-acquired Macro-Switar:

http://www.photomacrography.net/forum/v ... 1&start=15

Although the hood is detachable, the front of the lens is recessed by about a hood depth and a half, such that I wonder that the actual hood was ever thought necessary. The rear of the lens is about flush with the mount.

Harold

[rjlittlefield]

I put the reversing ring on my extension tubes, and no vignetting. I don't understand fully.

Take everything off the camera and "sight down the bore". Or leave everything but the lens on the camera, and look through the bellows back to where the corners of the sensor will be. There could be something mechanically intruding into the light path.

Can you post here one of the vignetted images? Sometimes the form of the vignetting will give a clue.

--Rik

[PaulFurman]

thartl,
I'll try to help, I'm fairly new at some of this so don't take it as gospel.

I have been using my canon 5dmkii with 3 kenko tubes (12mm, 20mm, and I think 36mm,) a canon 135mm with a reversed canon 50mm. Its been producing decent images - a tad soft.

My reversing ring finally arrived that allows me to reverse my 50mm on my bellows. What I found was disheartening. I have just as much magnification with the other set-up but a little less dof and a little harder to focus,

Less DOF can be good thing if you do stacking with software, although regular lenses are usually sharper stopped down some, opening up gives more light and precision. Stopped down on bellows can be really dark.

Reversed normal lenses should do best with lots of bellows & extension so that distance is closer to the designed minimum focus range. The other side works best about 45mm from the subject as designed about 45mm from the film/sensor.

and more vignetting.

Does the lens stop down with closed aperture when un-mounted and used in reverse? I believe you can set the aperture on the camera first then pull it off & it'll stay there for Canon lenses.

Also, I noticed that the magnification doesn't change with the reversed 50mm when the bellows are fully extended (at least not alot.

Get a metric scale/ruler and measure your magnification. Your sensor is something like 25mm wide so if you can see 25mm, that's 1x, if you see 12mm, that's 2x. Easy and precise.

One of things I was really excited for with the reversing ring, is that my 50mm has a built in lens hood, so if the lens is mounted normal, and used with bellows, the subject has to be inside the hood and there is not really anyway to light it. With a reversed lens I eliminate that problem.

If the subject is closer to the lens than the mounting distance (about 45mm), then it's usually better to use reversed. Makes sense if you think about it as that's what it's designed for.

But it isn't giving me the magnification I want nor the clarity.

More extension, put the tubes on the bellows but then you have to be real careful about vibration & shutter lockup. Long exposures should make the initial shutter bounce have less effect as most of the exposure is after it's calmed down.

[thartl]

I put the reversing ring on my extension tubes, and no vignetting. I don't understand fully.

Take everything off the camera and "sight down the bore". Or leave everything but the lens on the camera, and look through the bellows back to where the corners of the sensor will be. There could be something mechanically intruding into the light path.

Can you post here one of the vignetted images? Sometimes the form of the vignetting will give a clue.

--Rik

Not stacked just a sample of the vignette I will look at the "sight down the bore" deal later.

[rjlittlefield]

It looks like the hole in those extension tubes is not big enough to let light reach the corners of the sensor. I've never worked with full-frame and tubes in a Canon mount, so I've not run into this one before. Removing the tubes may solve the problem, or you may have it again with the rear mount on your bellows. Conceivably it could be a problem even with just the camera side of the mount, though I've never heard of that being a problem.

Paul's comment about stopping down the lens is important. Even reversed, something like an f/1.8 lens wide open on bellows will not work well. Consider the series at h[url]ttp://www.photomacrography.net/forum/viewtopic.php?t=424[/url], second panel, second column. That lens is awful at f/2, but gets pretty decent at f/5.6.

I've always been nervous about that trick of removing a lens while it's stopped down with the preview button, but it's widely published and I've never seen a trouble report.

It would be far better, though, to invest in something like a used enlarging lens. EL Nikkor 50 mm f/2.8 is popular and high quality. An enlarging lens will provide you with both a convenient manual diaphragm and optics that are designed better to work at macro distances.

--Rik

[thartl]

EL Nikkor 50 mm f/2.8 is popular and high quality. An enlarging lens will provide you with both a convenient manual diaphragm and optics that are designed better to work at macro distances.

They make these canon mount? (Silly question cuz I can look for myself, but I have always over looked this thinking they were strictly Nikon lenses?)

Also, I believe I might be stopping my lens down and removing it incorrectly in order to maintain the desired ap. I think (not having paid that much attention to what I do,) that I stop it down, turn the camera off, remove the lens, and then attach as needed. You are saying the correct way is to remove the lens while in the preview mode of reviewing photos?

I also own a 30d and a 20d. I might have to try the 30d as my designated macro with the 60% crop. I just LOVE the new 5dmkII though.

[augusthouse]

thartl wrote:

They make these canon mount? (Silly question cuz I can look for myself, but I have always over looked this thinking they were strictly Nikon lenses?)

You can reverse mount most EL-Nikkors onto just about anything. What is the thread size of your reversing ring? A step ring suitable for that thread to 40.5mm will attached nicely to the filter thread on a 50/2.8 EL-Nikkor.

thartl wrote:

You are saying the correct way is to remove the lens while in the preview mode of reviewing photos?

I've not had occasion to do this myself; but I expect that would be done after pressing the Depth-of-Field Preview button on the DSLR.

Craig