Using Stackshot

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macbates
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Joined: 13.01.2014 21:18

Using Stackshot

Unread post by macbates » 30.07.2016 21:15

I’m having trouble figuring out how set Helicon Remote parameters when using a Stackshot. Specifically, what are the units in the ‘Interval’ field? When using the Stackshot standalone, I set the near and far focus points manually, then calculate the depth of field, and based on that, determine the step interval. For example, using a Canon MP-65E lens at 3x and f/8, the DOF is 0.249 mm. Knowing that, I can set the step size on the Stackshot to 0.125 mm so I have lots of overlap.

When using the MP-65 and Stackshot with Helicon remote however, all I get is a total of 55 steps after setting the A/B (near/far) points. Clicking the ‘Auto’ button doesn’t do anything, and using the DOF calculator shows a distance of 17.76 m to the subject (should be 51 mm). If I put in 5.1 cm as the distance, it shows a DOF of 0, which is not right (although close). The help file doesn’t help, although it may be more for using remote focusing than a Stackshot.

If I know what the step size in mm should be (0.125 mm, for example), how do I tell Helicon Remote to use that value? Alternatively, how do I know how many steps to enter into Helicon Remote so that each step (interval?) is the correct size? It seems that Helicon Remote uses different terminology than Stackshot, which makes it difficult to know how to set things up. Any ideas from folks who have a Stackshot and use Helicon Remote?

- Ken

MikeCT
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Joined: 08.04.2014 19:56

Re: Using Stackshot

Unread post by MikeCT » 01.08.2016 03:03

Since you can control everything using Remote, there is no need for calculations. Remote will read all your camera settings, lens, speed, f stop and ISO. Once you set the start and end points on screen the program determines how many shots are needed (you can override this if you wish). Press the Start Shooting button and it will take over.

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Stas Yatsenko
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Re: Using Stackshot

Unread post by Stas Yatsenko » 01.08.2016 11:12

One important addition to Mike's answer: when using Auto mode with Stackshot, you have to press the "DOF" button and input the distance to subject. Only then will the automatic calculation be correct.

The step size (unit) is defined in preferences -> Stackshot. If you get the DOF of 0 (I. e. you need higher precision / smaller step), you can adjust the step down, but no lower than 0.05 mm which is the minimum step Stackshot can perform.

macbates
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Joined: 13.01.2014 21:18

Re: Using Stackshot

Unread post by macbates » 02.08.2016 02:48

I tried the suggestions, but they don’t seem to work. My setup is a Canon 5D3 with a Canon MP-65 lens. Using the Stackshot I proceed as follows:

1: Set the near and far focus points (A and B). Distance shown is 70/70.
2: Return to the near (A) position
3: Ensure that ‘Auto’ is checked and click the ‘DOF’ button
4: Ensure distance to subject is 5.1 cm, then click ‘Close’
5: The ‘Shots’ and ‘Interval’ fields both show a ‘?’
6: Click “Start shooting’

The result of the above is one image. Clearly not what I was after. From this, it appears that ‘Auto’ doesn’t automatically set the number. of shots. In step 4 above, the DOF is shown as ‘0’, but in preferences, the step size is already set to 0.05 mm, which is the smallest that HR supports.

Since Auto doesn’t seem to work, it appears that my only recourse is to uncheck Auto and set the ‘Interval’ field manually. At f/8 and 3x on the MP-65, the DOF is 0.249 mm, so if I want a step size of 0.1 mm (for example) and the HR step size is 0.05 mm, I need to set the Interval field to 2. This works, but having an automatic calculation as MikeCT suggested would certainly be easier and less error prone.

Am I missing something, or is it just that the MP-65 lens being a fully manual one with no focusing ring is messes things up?

- Ken

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Stas Yatsenko
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Re: Using Stackshot

Unread post by Stas Yatsenko » 02.08.2016 10:05

DOF being 0 is the problem, clearly. It means that with the current settings (distance to subject, aperture and focal length) the DOF is less than one step, which makes focus bracketing impossible. set a smaller aperture or shorter focal length (if it's a zoom lens).

macbates
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Joined: 13.01.2014 21:18

Re: Using Stackshot

Unread post by macbates » 02.08.2016 14:46

Thanks Stas, I understand now.

The real problem seems to be that the effective aperture of the MP-65 lens is dependent on the magnification factor, and HR doesn’t know that. At a distance of 51 mm, an aperture of f/8 and a magnification of 3x (which I’m using), the effective aperture is f/32, even though the lens reports f/8 to HR. The f/32 aperture gives a DOF much greater than 0 (0.249 mm), which allows for plenty of steps.

I think that the combination of the effective aperture of an MP-65 being quite different than the reported aperture plus the apparent lack of distance information being sent from the camera to HR is what’s making HR think that the DOF is so small when in actuality it’s (comparatively) quite large. For HR to correctly set the DOF, it needs to know the magnification amount, which can then be used to determine the effective aperture and distance to the subject (focal plane distance is fixed and dependent on the magnification in an MP-65). With that information, the DOF can be calculated and the correct number of steps can be set. I doubt if the magnification factor is available from the lens, so I suspect that I’ll always have to use manual mode.

- Ken

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Stas Yatsenko
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Re: Using Stackshot

Unread post by Stas Yatsenko » 03.08.2016 14:13

I understand. No, the lens doesn't report magnification / focus distance so you'll have to set the number of steps manually.

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