Cicadas

Richard Dutton said:

Tord S Eriksson said:

Peter in Canberra said:

what is the working distance with the FT1 + 40 micro?

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It's roughly the same as the Sigma 105/2.8 OS HSM macro on my FX camera, something like 20cm.

(I just tested it and my guesstimate was pretty accurate).

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Is this with the 40/2.8G micro focussed to get 1:1 effective ? I must be missing something here.

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My mistake, I was referring to my normal focusing distance shooting flowers, sorry!

Richard Dutton said:

The MFD is 163 mm on any sensor and the lens length is 64.5 mm but when you focus it in the front grows and so instead of about 163-64.5-46 ( lens reg distance ) ~ 52mm which AP quotes, it is less - actually only about 35 mm ( front of lens to subject ).

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That seems to be correct!

Richard Dutton said:

So I wondered, above , if you reduced the magnification which is 1:1 at MFD by focussing at more than the MFD, taking account of the crop ratio to give an effective magnification of 1:1, how much more working distance can you recover ?

The working distance of these short FL macros is always small - it's only about 2-3 inches on the versions of the 60mm/2.8. I prefer longer - the Tamron SP90 working distance is about 140 mm but, again on aps-c< I back off a bit to get nearer 200 mm at effective 1:1. It also lets the AF work better.

Richard

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According to the magnification scale on the lens, you get 1:1 at approx. 16cm from the focal plane, and that seems to me to be correct. So what that ends up like on a Nikon 1 I have no grasp of (my math has deteriorated with age, and it never was any good)!

So I took a couple of shots of my standard Apple keyboard (so old it uses a cable!), one shot at 1:1 setting and one at 1:2 setting. hope this is useful!

The key covers the sensor almost perfectly at 1:1, just slightly bigger.




1:1




1:2

There might be minor errors as I set the size as well as I could, and I don't know how well the scale is calibrated.

--
tordseriksson (at) gmail.....
Owner of a handful of Nikon cameras. And a few lenses. DxO PhotoLab user.
WSSA #456

Richard Dutton said:

Richard Dutton said:

[snip]

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Is this with the 40/2.8G micro focussed to get 1:1 effective ? I must be missing something here.

The MFD is 163 mm on any sensor and the lens length is 64.5 mm but when you focus it in the front grows and so instead of about 163-64.5-46 ( lens reg distance ) ~ 52mm which AP quotes, it is less - actually only about 35 mm ( front of lens to subject ).

So I wondered, above , if you reduced the magnification which is 1:1 at MFD by focussing at more than the MFD, taking account of the crop ratio to give an effective magnification of 1:1, how much more working distance can you recover ?

The working distance of these short FL macros is always small - it's only about 2-3 inches on the versions of the 60mm/2.8. I prefer longer - the Tamron SP90 working distance is about 140 mm but, again on aps-c< I back off a bit to get nearer 200 mm at effective 1:1. It also lets the AF work better.

Richard

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I think we need to clearly define a few things in this discussion. My understanding is:

1. Magnification refers to the size of the image created on the sensor compared to the size of the subject.
2. Magnification of 1:1 means the image size is the same as the subject size.
3. The magnification with any lens is the same regardless of format if the focus distance is the same. For instance, a Nikkor 105/2.8 macro at minimum focus delivers a 1:1 image on FX, on DX, and on CX sensors.
4. On an FX camera a subject 24mm by 36mm will fill the frame at 1:1; on a DX camera a subject 15.6mm by 23.5mm will fill the frame at 1:1; on a CX camera a subject 8.8mm by 13.2mm will fill the frame at 1:11.
5. I'm not sure what "effective" magnification means, but I think your definition would be filling the CX frame (8.8x13.2mm) with a subject 24x36mm; that is, with a subject that is 2.7 times larger linearly. So that would be setting the lens for a magnification of 1:2.7 instead of 1:1. So you don't focus as close and therefore have a greater working distance.

RichDitch said:

Richard Dutton said:

RichDitch said:

[snip]

Click to expand...

Is this with the 40/2.8G micro focussed to get 1:1 effective ? I must be missing something here.

The MFD is 163 mm on any sensor and the lens length is 64.5 mm but when you focus it in the front grows and so instead of about 163-64.5-46 ( lens reg distance ) ~ 52mm which AP quotes, it is less - actually only about 35 mm ( front of lens to subject ).

So I wondered, above , if you reduced the magnification which is 1:1 at MFD by focussing at more than the MFD, taking account of the crop ratio to give an effective magnification of 1:1, how much more working distance can you recover ?

The working distance of these short FL macros is always small - it's only about 2-3 inches on the versions of the 60mm/2.8. I prefer longer - the Tamron SP90 working distance is about 140 mm but, again on aps-c< I back off a bit to get nearer 200 mm at effective 1:1. It also lets the AF work better.

Richard

Click to expand...

I think we need to clearly define a few things in this discussion. My understanding is:

1. Magnification refers to the size of the image created on the sensor compared to the size of the subject.
2. Magnification of 1:1 means the image size is the same as the subject size.
3. The magnification with any lens is the same regardless of format if the focus distance is the same. For instance, a Nikkor 105/2.8 macro at minimum focus delivers a 1:1 image on FX, on DX, and on CX sensors.
4. On an FX camera a subject 24mm by 36mm will fill the frame at 1:1; on a DX camera a subject 15.6mm by 23.5mm will fill the frame at 1:1; on a CX camera a subject 8.8mm by 13.2mm will fill the frame at 1:11.
5. I'm not sure what "effective" magnification means, but I think your definition would be filling the CX frame (8.8x13.2mm) with a subject 24x36mm; that is, with a subject that is 2.7 times larger linearly. So that would be setting the lens for a magnification of 1:2.7 instead of 1:1. So you don't focus as close and therefore have a greater working distance.

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Yes exactly Rich ( especially 5 ) - rather better explained than my loose words.

It is useful that you can get more pixels ( assuming say 20 max on all sensors ) onto the 1:1 image in small sensor cameras and so, you can effectively magnify the image by 2.7, 2 or 1.5 on the relevant smaller than full frame sensor.

I know that this is obvious but trying to get e.g. 2.7:1 on a full frame sensor is mighty difficult with "ordinary" lenses and you can forget AF assist and so lens motor driven stacking - this is pushing towards extreme macro - you get this almost for free with small sensor/high pixel density cameras.

The late and much missed Nick Gray aka gardenersassistant did some exceptional work using m43 as well as being a kind and generous teacher in the field.

Yes Rich, thanks for listing these important and correct points. I think most of us here understand this but I have seen a lot of misinformation on other forums as to what is meant by 1:2, 1:1, etc. In the film days I would explain to someone that didn’t get it as follows: If you take a photo of a dime at 1:1, process the slide or negative, when you laid the dime on the image, it would or should be the same size, regardless of format.

Paul Pasco said:

Yes Rich, thanks for listing these important and correct points. I think most of us here understand this but I have seen a lot of misinformation on other forums as to what is meant by 1:2, 1:1, etc. In the film days I would explain to someone that didn’t get it as follows: If you take a photo of a dime at 1:1, process the slide or negative, when you laid the dime on the image, it would or should be the same size, regardless of format.

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Right.

I think the confusion can come from the "crop" factor. We can get in the habit of saying/thinking that a crop factor of 2.7 turns our lens into a lens 2.7 times as long (100mm "turns into" 270mm). It is then easy to think that the crop factor also turns our 1:1 macro lens into a 2.7:1 macro. I know that was my initial thought long ago before I did some actual thinking about it!

I can't say they are prettiest little things, but they're not as hideous as I once thought.

Thanks Paul for clearing this up. :-D

Nice work!

misterodd said:

I can't say they are prettiest little things, but they're not as hideous as I once thought.

Thanks Paul for clearing this up. :-D

Nice work!

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I love insects, so maybe I am biased? Glad I could help. ;-)