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Silvana

Wet diopter for a 60 mm macro lens

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Hi everyone,

I have a Nikon D850 with a 60 mm macro lens. I currently use a AOI +15 diopter but getting greedy for more magnification and wondering if anybody has experience with using the AOI UCL-900 PRO +23.5 diopter. It will be the only one higher than +15 that will work with this lens due to short focal length for the 60 mm macro lens. The +23.5 mm is rather expensive ($789 in US) and I am hesitant to buy without hearing from anybody else.

Thanks much in advance for thoughts.

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22 minutes ago, Silvana said:

Hi everyone,

I have a Nikon D850 with a 60 mm macro lens. I currently use a AOI +15 diopter but getting greedy for more magnification and wondering if anybody has experience with using the AOI UCL-900 PRO +23.5 diopter. It will be the only one higher than +15 that will work with this lens due to short focal length for the 60 mm macro lens. The +23.5 mm is rather expensive ($789 in US) and I am hesitant to buy without hearing from anybody else.

Thanks much in advance for thoughts.

I would guess that you have already discovered that the +15 diopter reduces your working distance significantly.  Diopters work by allowing you to focus closer, which means to get more magnification you need to reduce your working distance more than what you have now.  If you look at the Nauticam port charts, they list working distance for the CMC-1 as 4-73 mm, I know you don't use a CMC but it's reasonably close to a +15.  It gets 1.4x magnification - but gets that at 4mm.  I would guess that you might achieve 1.2x in practice with that small working distance.  I would say the +23 would likely be unusable on 60mm.

Diopters however vary in power with focal length.  The SMC-1 on a Nikon 105mm gives you up to 2.5x  and 53-95mm working distance.  Your +15 will get results in this ball park.  So the way to get more magnification is to use a 105mm lens - the +15 will give you a lot of magnification so you would probably also want a lower powered diopter to use with it as well.

 

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What Chris said.  At these macro ranges, working distance becomes the determining factor in usability, particularly with lighting.  I find it better to pull back a bit with a lower power diopter then crop later if I want a closer look.  I also miss fewer shots due to the very shallow plane of focus.  With a D850 you've got plenty of resolution to crop.  I know the satisfaction of getting the shot in camera though!  

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On 11/24/2021 at 4:45 PM, ChrisRoss said:

I would guess that you have already discovered that the +15 diopter reduces your working distance significantly.  Diopters work by allowing you to focus closer, which means to get more magnification you need to reduce your working distance more than what you have now.  If you look at the Nauticam port charts, they list working distance for the CMC-1 as 4-73 mm, I know you don't use a CMC but it's reasonably close to a +15.  It gets 1.4x magnification - but gets that at 4mm.  I would guess that you might achieve 1.2x in practice with that small working distance.  I would say the +23 would likely be unusable on 60mm.

Diopters however vary in power with focal length.  The SMC-1 on a Nikon 105mm gives you up to 2.5x  and 53-95mm working distance.  Your +15 will get results in this ball park.  So the way to get more magnification is to use a 105mm lens - the +15 will give you a lot of magnification so you would probably also want a lower powered diopter to use with it as well.

 

Thank you Chris. Are you saying a 60mm with a +15 diopter will provide less magnification than a 105mm with same +15mm? I don't have a 105 mm yet but from what I read, it provided more minimum focal distance rather than more magnification. Thanks!

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In general yes, for the same diopter you can more magnification with a longer lens than a shorter one.

Bill

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26 minutes ago, Silvana said:

Thank you Chris. Are you saying a 60mm with a +15 diopter will provide less magnification than a 105mm with same +15mm? I don't have a 105 mm yet but from what I read, it provided more minimum focal distance rather than more magnification. Thanks!

Yes that is correct, the diopter power increases with focal length.  Also Diopters in general work by allowing you to focus closer than your current minimum focus distance.    The 60mm macro has 50mm working distance from front element at 1:1.  while the 105mm has 150mm of working distance.  So the diopter on a 105mm has more capability to focus closer than it does on the 60mm.   

So in theory the get the same magnification but in practice it's easier to get to 1:1 with the 105mm as you have more working distance and easier to light the subject.  Of course the 60mm is more practical if you are also shooting  larger subjects on the same dive allowing you to get closer.

Your main issue with the 60mm macro is that 1:1 you are already down to 50mm from the front element, when you add in the port glass that is more like 40-45mm of working distance and to get more magnification you need to focus even closer. 40mm is already very close and difficult to light your subject, which is why I suggested that in practice you might be lucky to get 1.2x with the 60mm macro.  At the same working distance as your 60mm at 1:1 you would get around 2- 2.5x magnification with a 105mm lens and a +15 diopter.

I think though you might find a +15 on a 105mm a bit much to deal with, Depth of field is almost non existent.  at 1:1 DOF is about 1.3mm at f16.  This reduces to 0.5mm at 2.0x magnification, so you have to be absolutely rock steady to keep the focal plane on the subject.  This is why I suggested using a lower power diopter.   This episode of Wetpixel live discusses macro closeup lenses and is worth a watch:

 

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On 11/28/2021 at 6:11 PM, ChrisRoss said:

Yes that is correct, the diopter power increases with focal length.  Also Diopters in general work by allowing you to focus closer than your current minimum focus distance.    The 60mm macro has 50mm working distance from front element at 1:1.  while the 105mm has 150mm of working distance.  So the diopter on a 105mm has more capability to focus closer than it does on the 60mm.   

So in theory the get the same magnification but in practice it's easier to get to 1:1 with the 105mm as you have more working distance and easier to light the subject.  Of course the 60mm is more practical if you are also shooting  larger subjects on the same dive allowing you to get closer.

Your main issue with the 60mm macro is that 1:1 you are already down to 50mm from the front element, when you add in the port glass that is more like 40-45mm of working distance and to get more magnification you need to focus even closer. 40mm is already very close and difficult to light your subject, which is why I suggested that in practice you might be lucky to get 1.2x with the 60mm macro.  At the same working distance as your 60mm at 1:1 you would get around 2- 2.5x magnification with a 105mm lens and a +15 diopter.

I think though you might find a +15 on a 105mm a bit much to deal with, Depth of field is almost non existent.  at 1:1 DOF is about 1.3mm at f16.  This reduces to 0.5mm at 2.0x magnification, so you have to be absolutely rock steady to keep the focal plane on the subject.  This is why I suggested using a lower power diopter.   This episode of Wetpixel live discusses macro closeup lenses and is worth a watch:

 

Thank you Chris, this is very helpful and also thanks for the link to the previous videos and discussions. One thing I am sure of, I am not buying the +23 diopter :)

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Hi, for the money you might take better photos with a Nikkor 105 mm macro, than with a diopter.
The 105 is an excellent lens and used ones come up for sale at reasonable prices.

The drawback is that you are committed to one lens or another, while the diopters can be flipped during the dive. But the gain in quality makes up for this,  a matter of personal choice...

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I don't know about the IQ of the Nikon 60  vs the 105, but both are 1:1 lenses. The DXo boys think the 105 is slightly better in terms of accutance than the 60 but they are very comparable. All that being said, I think the OP was interested in magnification.

Bill

 

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