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WFTF Range Finding on dark lanes and targets  

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Cloud9AG
(@cloud9ag)
Joined: 1 year ago
Posts: 51
May 4, 2019 10:59  

At the recent Cajun Spring Classic, I struggled hitting targets at 35-55 yards on dark lanes shooting WFTF Springer.  With my Sightron 10-50x60 set at 50x, I could focus clearly on the target faceplate and feel like I accurately ranged it 95% of the time, but I only hit like 20% of those targets on Belle Terre.  There wasn't any wind that morning, and I was nice and stable with a gun shooting well.  I even checked my guns 25 yard and 55 yard clicks after the match ; they were both within my own error, so I don't believe the rifle was shooting differently that day.  

Any advice on hitting targets in the dark?

Jeff Cloud


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Paul Porch
(@paul-porch)
Joined: 1 year ago
Posts: 105
May 15, 2019 06:34  

Jeff,

I thought I'd comment on some of the subjects here.

First, addressing the dark targets, especially the long ones. For me, ranging a long target in the dark was not a problem I hit most of them except for two. But I believe they were more of a wind issue. I dropped them the second time with wind correction. My problem was my positional shots....

I range and shoot on 30 power. .

I added an occluder for my left eye on my scope

It helps to use binocular vision for better depth of field. Even though the left eye only sees black. 

It takes a bit of practice to not automatically close your left eye. But on especially hard to range targets, for me it really brings them into focus better.

Watch the Olympic level shooters in 10 meter. They all use one for a reason. 

On the reducers that Hector mentioned, I HATE REDUCERS!.

It's One reason why  I don't offer them on my  targets. (Unless a customer requests to have them).

However, that said, I found the reducers at the Cajuns to my liking. They were on the ftont and brightly polished looking on the dark targets. I was able to focus in the center of the kill zone easier. It allowed me to completely ignore the Target and just focus on the KZ. Like David Slade often says, 'Just aim at the round bits"!

Many times I use the linkage on the target to get my range. If that is too fuzzy, dark, or obscure, I use the block or the clamp.

Regarding Hector's mention of the paint on targets. On all my targets, I use Rust-Oleum 2X. If you shoot some of the thinner targets like Gamo's, the impact flakes off large chunks of paint. The thinner construction helps this effect too.

With Rust-Oleum 2x, it only makes a pock mark where the pellets hits.

To sum up on my recommendation for trying to range those dark targets..... Try the two eye method. it takes a little getting used to, but it works well for me.

Oh, this is just for the focus issue in the dark. It does not address issues with heat shift in a scope. The Sightron's are notorious for this. I use a March 8-80 and it really has not had a temp shift like my Sightron. With two eyes I still range fine, but I need a temp shift chart for the Sightron.


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phepler
(@deadeye)
Joined: 1 year ago
Posts: 73
May 15, 2019 13:35  

Slightly different situation as I shot hunter PCP at the cajun-

I know what you mean about dark lanes and targets! With a 16x scope it can be challenging to range correctly. I too leave both eyes open and definitely use a lighted reticle on dark targets. To help with ranging I made a blanket that I throw over my head and scope- sort of like the old time cameras. I used it on a few of those dark lanes at the cajun to help me see the target and range better. Especially when I'm sitting in the sun, but the target is down a long dark lane. 

My 'blanket' is black on one side and white on the other. I made it that way on purpose. The white faces up and black down when I'm using it to range. White side is also used to cover my rig when I'm sitting in the sun to keep the gun from getting hot.

It may look silly, but I believe it helped me on a few dark targets. And a few points can make a big difference!


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Hector J Medina G
(@hector-j-medina-g)
Member of Trade
Joined: 1 year ago
Posts: 210
May 16, 2019 09:26  

Dan;

I don't quite get the "circles of confusion" thing. I understand that, in reality when talking about film or about CCD's the circle of confusion is defined by the size of the grain, or the size of the pixel in the detector/sensor, but how does that apply to the human eye? Do we have a "pixel size"  for the retina?

If you have further information, it would be greatly appreciated.

I  use a slightly different protocol from what the A-Team uses, and I do advocate the "hand memory"  approach of trying to find the center of the "most focused" setting when ranging.

I do, however, always advise to range while concentrating on the smallest possible object available with a pattern, and that is, usually, the chain or the swivel and link between faceplate and reset line. 

Thanks!

 

 

 

 

HM


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JimW
 JimW
(@jimw)
Joined: 1 month ago
Posts: 13
May 16, 2019 17:00  

Great discussion!!

Remember the split center focus unit at SLR lenses?  Would be a neat feature for field target scopes!

I have never head the term 'circles of confusion' but it's the perfect description of what happens as the image goes out of focus from my days with SLRs.  For 35mm film you are looking through glass (no sensor/pixels) so you get to see the circles form and dissolve in perfect resolution, in video and other digital cameras things just get fuzzy due to sensor specifications.  

You can get large circles of confusion in dark settings with bright lights and a seriously out of focus digital camera.  More so if it's a moving image, the circles will move like lens flares as the subject moves.  The closer you get to focused the more fuzzy the images gets (the sensor can't pick up the micro circles of confusion like our eyes can).

I have noticed on my Nikko that when I go over the top of the target in terms of ranging (too far) the image starts to turn slightly pink/purple and then I know I am too far even though it is still mostly in focus.  If I refocus and stop just prior to the pink hue, then I am spot on.

 


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drputz
(@drputz)
Joined: 1 year ago
Posts: 3
May 16, 2019 17:24  

 

The way I understand circles of confusion is that, say you are looking at the point of a beak on a bird field target. Light hits that point and reflects in all directions, some of which get captured by the scope. The light spreads out from the target into a cone from the beak. We are looking at the bottom, round fat end of that cone. The scope focuses this fat end back down to a point again on the focal plane. The smallest size that we individually can discern as a circle vs a point is the circle of confusion. Beyond that point the beak is "in focus" to our eye. Note that the circle is not necessarily a perfect point yet, but would need to focused further. A perfect focus would also be equivalent to "in the same plane" of the reticle. With low light, there is not enough light to discern a reasonably small circle, so we "accept" a larger circle, which is a focus short of the perfect parallax. The circles of confusion can be seen on good portrait photos as background boketh. The smallest circle is dictated by the media, be it film, digital or our eye. 

I hope that helps  

Dan 

 


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