Sharpness test. Baader U vs. ZWB1/S8612 stack

[Nate]

Recently went and did some shooting with zwb1 2mm/S8612 2mm stack on the EL Nikkor 80mm, nothing great to share because the sharpness wasn't there. Decided to do a test on a metal thermometer.

        For this test, I was about 7ft away, 365 torch mounted on top of 77D on tripod. I re- re focused each filter change on EL Nikkor 80.

        Raw Pics are cropped in to a 5-10% portion of original  in Faststone, and resized to approx. 1000px in photoscape with no further editing.

        White balance was for the Baader, didn't feel it was too important, and/or forgot. 

 

Baader U

 

ZWB1/S8612 both 2/49mm threaded, tried changing around filters with same outcome.

 

As you can see, for my particular setup, I will not be using that cheap zwb1 for anything but torch filtration.

 

Is this common with un cemented stacks? Or do you think it's mostly poor glass.

It also might be that I sit 1 foot away from a 32in 2560x1440 gaming monitor too

                                                                                                                                     Thanks

[ulf]

I have not seen any sharpness issues with my stacks.

The second, blurry image seam to be blurred mostly in vertical direction.

Normally that is a sign of motion blur.

 

I normally use converted flashes to avoid motion blur.

Early when I just used sunlight for illumination 90-97% of my images was blurry due to motion caused by the wind.

[Nate]

Decided to put filters together, and screw back to one 49mm housing with S8612 on the outside. Seemed to have gained some sharpness, but still not as good as the Baader filter alone.

 

ZWB1 behind S8612 in one housing

 

[Nate]

17 minutes ago, ulf said:

Normally that is a sign of motion blur

My torch was stationary mounted on camera. I have taken probably 10 shots for each to see if motion was an issue, but all turn out the same. I'm thinking that UV filter I ordered from Amazon and shipped from China way before I got the Baader is of lesser quality. It was only $40.

[Fandyus]

Might be due to striations or some other structural imperfection. It's unfortunate but it happens with cheap filters.

But for me, I'd rather buy a cheap filter twice, paying ~40€ than buy an expensive one for 200€.

[dabateman]

I do find that Baader venus has the best micro contrast of all the filters I have.  

However your zwb1 image does look to have motion blur.  What are the exposure time?  Did you use mirror lock up or a mirrorless camera? 

You might have mirror vibrations or shutter vibrations in the zwb1 shots.

Try electronic shutter and mirror up. Also make sure to use a tube like hood, to avoid glow from lights being picked up.

[ulf]

You can also check by rotating the filter, to test if the problem is caused by striations. Then the blur-direction will change.

If it is motion blur, it is caused by a motion between camera and motif and has nothing to do with the light source.

 

When I use my flash I freeze the motion and avoid blur. That is the advantage with flash illumination over lower intensity light sources.

[Nate]

37 minutes ago, ulf said:

You can also check by rotating the filter

That's it!    I rotated filter and sharpness came and gone 2 times until it got tight while on 10x live view zoom.

[Nate]

51 minutes ago, dabateman said:

You might have mirror vibrations or shutter vibrations in the zwb1 shots

I don't think this is the issue, because I used this camera for astro a lot in the past. I'll play with the mirror lockup feature though, to see if this helps any, Thanks

[Nate]

56 minutes ago, Fandyus said:

I'd rather buy a cheap filter twice, paying ~40€ than buy an expensive one for 200€.

This is some thing I've done for sure, except some take a month to get if over seas

[Nate]

Rotating outside filter until it unscrews. Focus comes and goes.  I can see a visible difference, hope it shows on here.

Shows up pretty good.

 

[nfoto]

That filters or anything else in the optical path of light can alter sharpness has been known like forever. Striation, lack of parallel sides, uneven surface polish, ...., and so on.  Cheap filters tend to be the biggest culprits in this respect as I have had more than one incidence with a filter that threw off infinity focus or otherwise adversely impacted the outcome. Such issues have never been encountered with my Baader, B+W, or Hoya filters purchased over the years.

[Nate]

1 hour ago, nfoto said:

Such issues have never been encountered with my Baader, B+W, or Hoya filters purchased over the years

Thanks for the input, I think I'll stick to reputable brands in the future and not use these filters anymore for photography. I am thankful that my Baader U and EL Nikkor exceed my expectations.

[dabateman]

Andrea added the Baader venus to the list of beginner filters saying that its not really a beginner filter.

However,  if you do just buy a Baader venus filter and the Nikkor metal old 80mm f5.6 EL lens as your first beginner kit. You are pretty much set for almost anything.  Then when your not, or need a different look, than you can play with all the different filter combinations to get various colors. 

 

My beginner UV kit for 10 years was the stock Olympus E3 (leaks uv like a converted camera, just poor IR), Olympus 35mm f3.5 macro lens and the Baader venus u filter.  Worked well. I didn't go all filter crazy until I bought a UAT 85mm and got a full spectrum converted Em1mk1. 

[Nate]

30 minutes ago, dabateman said:

Baader venus filter and the Nikkor metal old 80mm f5.6 EL lens as your first beginner kit

I agree with this. But I got to add that I did buy a second old Nikkor 80 and the glass was in pretty bad shape, and not as sharp as my first. For $70 I have spare parts and got to know what's inside the lens is a plus for sure.

[Nate]

1 hour ago, dabateman said:

I didn't go all filter crazy until I bought a UAT 85mm

Ha Ha, that lens would be amazing. Sounds like when I wanted the best thermal spotter and no one was stopping me.

[Andy Perrin]

I’ve always wanted but never owned a Baader. I have my 330WB80 filter for dichroic but I mostly ended up using S8612 1.75mm + UG11 2mm. It is not the ideal stack, but as we’ve discussed recently, the filter doesn’t need to be perfect to get good results, just “good enough” (and made of high enough quality materials to do the job, regardless of whether you do the quality assurance yourself or let Schott/Hoya do it for you…). I ended up with an absorption only stack because I was having issues with dichroic color shift near the edges, especially on the full frame camera. 

[Nate]

@Andy PerrinAbsolutely.   One of these days I'll upgrade to full frame and mirrorless since I've never used the eye look through thingy on any of my cameras.

 

[Andrea B.]

With UV there are two important additions to shooting procedures because of long exposures.

 

Remote shutter release for DSLR or for mirrorless.

I love those Vello wireless remotes, but a plain plug-in shutter release is lots less expensive.

 

Mirror lock-up or shutter release delay. This setting is necessary for DSLRs.

Let the vibes die down before firing the shutter.

Some of the mirrorless have electronic first curtain or all electronic shutters. Very nice.

(I still use shutter release delay for elec 1st curtain.)

 

If you already know this stuff, kindly ignore. Perhaps this will help newbies.

[Andy Perrin]

I have an infrared camera remote with one button on it to trigger the shutter. Is that what You mean? It was like $10, though, so hardly qualifies as expensive.

[Nate]

25 minutes ago, Andrea B. said:

shutter release delay

All my cams are on a 2 sec delay. This is good advice. I think I have 3 remote shutters, being into astrophotography as well, I have most the goodies.

[Andrea B.]

I have an infrared camera remote with one button on it to trigger the shutter. Is that what You mean?

 

Mine are Vello Free Wave remotes. I don't recall what I paid for it, but I'm thinking at least $50 about 3 years ago.