Two Stackshot Questions

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Lindaavitt
Posts: 23
Joined: Mon Dec 18, 2017 7:49 am
Location: Austin, Texas

Two Stackshot Questions

Post by Lindaavitt »

I've had a chance to run through a few stacks using my new Stackshot, and I'm really loving it. Two questions.

1. To determine the step size, I'm using Table 2-A from Zerenesystems.com. For example, the table shows that with magnification of 1:1, using f5.6, the step should 0.28. Should I set exactly 0.28 for the step, or go a little less than that? If so, how much less?

2. Where the trigger cord plugs into the Stackshot, it's a very loose fit -- and I mean, really loose. Like the slightest bump causes it to lose the connection.
Has anyone else had that problem and fixed it?

Thanks!
Linda

mawyatt
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Joined: Thu Aug 22, 2013 6:54 pm
Location: Clearwater, Florida

Post by mawyatt »

I'm sure others more qualified than myself will provide some valuable guidance but believe this answers your question to the best of my knowledge.

Yes, the step size should be lower than the DoF, I usually go for about 70% of the DoF.

If the Stackshot connector you are talking about is the RCA type plug (plugs into the Stackshot control box), you can just slightly bend in the 4 ground tabs on the plug outside so you get a snug fit.

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

rjlittlefield
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Post by rjlittlefield »

1. Choosing step size is always a matter of balancing tradeoffs. The numbers given in that table are good for most subjects, but troublesome subjects with complex structure or a lot of short-wavelength blue colors can require smaller steps to capture all the detail that the optics have to offer. I normally round down to some nearby "friendly" number, probably 0.25 mm instead of 0.28 mm, mainly to facilitate doing rough calculations in my head. If I suspect the subject might be troublesome then I drop smaller, say to 0.20 mm, maybe even 0.15 mm or 0.10 mm, because it's less painful to shoot extra frames than it is to discover after stacking that I didn't have enough. If you need an optimized number because you have a lot of similar stacks to shoot, then there's no substitute for experimenting to find the largest step that will still produce good output. If safe is more important than optimum, then a reasonable strategy is to use say 70% of the values in the table.

2. The trigger cord ends in an "RCA phono plug" that has an exposed thin metal shell. That shell can be slightly deformed with pliers to make a tighter fit. Just be sure to approach slowly and gently so that you don't make it fit too tight, or not at all. If your cable is like mine, then the plug has an essentially solid cylindrical shell, no slits that form tabs, but it should work fine to just flatten the cylinder slightly.

--Rik

Lindaavitt
Posts: 23
Joined: Mon Dec 18, 2017 7:49 am
Location: Austin, Texas

Post by Lindaavitt »

Thanks, mawyatt and Rik.

1. That's good information. I'll start with 70 percent. Never would have thought about short-wavelength blue colors, but that makes sense.

2. Yes, it's a phono plug with no slits. I'll very carefully do a slight deform. I'd been wondering if that would be okay.

Linda 8)

mawyatt
Posts: 2497
Joined: Thu Aug 22, 2013 6:54 pm
Location: Clearwater, Florida

Post by mawyatt »

If the RCA plug has no slits, then an old trick is to put a tiny piece of aluminum foil around the plug exterior cylinder ends. Just enough to decrease the inside cylinder diameter enough for a snug fit. Don't use so much foil that you can short out the center pillar though.

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

Lindaavitt
Posts: 23
Joined: Mon Dec 18, 2017 7:49 am
Location: Austin, Texas

Post by Lindaavitt »

Poor connection is “fixed” with pliers. Yay!

Mike, if this ends up coming loose, I’ll try your fix.

Linda. 8)

tevans9129
Posts: 129
Joined: Thu Nov 30, 2017 8:03 am
Location: TN

Post by tevans9129 »

Yours may be different but I had that problem with my Stackshot when I first received it and found out my problem was that I was not fully seating the connector. There was enough resistance that I thought it was seated but it was not. It might be worth a look.

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