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Sunex, 185° SuperFisheye 5.6mm F/5.6


ulf

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The topic below is a first attempt to write a more formal post for a lens.

 

I hope to be able to use the post as a template for future tested lenses.

It might be possible to have the post moved to a dedicated location in the future if Andrea and Birna agrees to do that.

I hope such a location can evolve to hold many topics for in detail information more in depth information than available the current Lens-sticky.

 

Please comment on you are missing in the topic below.

I will try to add missing things to the framework, even if it is not applicable to this lens.


Manufacturer's lens designation: Sunex, 185° SuperFisheye 5.6mm F/5.6

Manufacturer: Sunex, Inc., 5963 La Place Court, Suite #309, Carlsbad, CA 92008

Lens type: Circular fisheye

Focal length: 5.6mm

Aperture range: f/5.6 fixed

Intended Focus range: 0.5m - Infinity, fixed.

Available mounts: Canon EF, Nikon, other via adapters.

Sensor format/coverage: APS-C

Filter-thread/-mount: None

Introduction year: 2008?

Discovered as UV-Capable by: Birna

S/N of test object: C-2L05AG219

 

Lens review (VIS), on the web: https://www.kenrockw...per-fisheye.htm

 

Simplified transmission metric parameters*:

TVISmax (%) : 85%

T365nm (%) : 20%

UVHalfC (nm) : 380nm

UVKDSC (nm) : 360nm

* Definitions and comments at the post's end.

 

Spectral transmission graphs:

post-150-0-71808700-1603627551.png

The transmission measurement accuracy into the NIR range is less good due to limitations in the light source.

 

post-150-0-62702800-1603627589.png

 

General comments about the UV-reach:

Wide angle lenses from 28mm and shorter normally have a poor UV-transmission.

They normally do not need a very deep cutoff for the typical usage for landscape photography as the sunlight contain little UV below 330nm.

Even some transmission closer to 400nm might be enough for that.

For such a wide lens as the Sunex the transmission unusually is good and still useable, after a proper white-balancing.


Filters and how to use them on this lens:

Fisheye lenses cannot be used with front-mounted filters and this lens has no holder for rear mounted gelatin-type filters.

 

It is possible to use rear mounted filters, either in lens mount adapters for mirrorless cameras like Sony A-series etc, or placed directly in the camera.

 

An alternative, if space in the camera allows, is to putty-mount a filter directly against the lenses rear element mount ring.

The rear lens element is recessed and thus safe and the ring provides a good reference plane for orienting the filter normal to the optic axis.

post-150-0-89585200-1603630445.jpg

Here a filter glass from a B+W 550nm long-pass filter is putty mounted.

The rear element's diameter is small enough that it is possible to mount 25mm filters.

My Omega 330W80 Improved, used for the UV-image below, is mounted in a 27mm-filter ring and works well to mount as it is.

 

When using rear mounted filters it is important to realise that they shift the focussing to infinity as the filter-glass gives a shorter optical path length mimicking a forward shift of the lens.

 

For wide-angle lenses even a short shift is very critical and can destroy sharpness at infinity.

 

The Sunex lens has a factory set critical focus point, that can be readjusted.

That has to be done if introducing rear mounted filters.

 

The massive lens-block is mated to the lens-mount parts with an external M42x1mm thread.

The lens-block is then locked with four grub screws placed in it's cylindrical side.

The screws can be loosened with a 1.5mm hexagonal (Allen)-screwdriver or bit.

When these screws are loosened the lens-block can be rotated in the mount and thus shifted back and forth, to set a proper sharp infinity.

 

When using different filters there is an optimal setting for each filter and it is convenient to make a scale to quickly set proper focus-point when changing filters.

post-150-0-62997900-1603630871.jpg

Here is my scale for the filters I so far have found the settings for.


Canon EF mount mechanics quirks:

The mount do not have any coloured indication dot, guiding the rotation angle when mounting the lens.

When mounting the lens by turning it, the correct way, it distinctively clicks in place at the end point as any normal lens.

The mount also lacks the feature that normally stops the reverse rotation beyond the engage/release-point when removing the lens from the camera.

These are no big problems when you get used to them, but at first they can cause confusion.

Beside these quirks the mount is made with a very good precision.

 

Handeling and focussing:

As the aperture is fixed Aperture priority or manual settings is the only way to use the lens.

If a scale with focus settings is used it is easy to reset to infinity focus and if a closer focus is desired, loosening the locking screws and turning the lens to a closer focus is easy. However then do not expect any flat field as the lens is not used as intended.

 

The main difficulty using this lens is to avoid getting your feet or shadow in the picture.

You also have to look for different compositions than with a normal lens as everything is shrunk and distorted.

This effect is shared with all super-wide-angle-lenses.

 

Flare and sun-stars:

The lens design and coatings is very good and there is seldom big problems with flare, even with the sun in the image.

There are no sun-stars as the fixed aperture is circular.

 

Sharpness:

I have found the lens impressing sharp.

My main usage has been for NIR and VIS+NIR photography.

 

Fisheye projection:

The lens deviates a bit from the ideal fisheye projection, pronouncing the central parts and squishing the edges.

This can be corrected almost completely by software like Hugin or LensFun by mapping the error and generating correction coefficients.

Darktable might be used to make the projection more pleasant by applying the lens-correction for another fisheye lens.

I prefer the correction made for Sigma 8mm 3.5 FX for that, but often no processing or correction is needed.

 

Chromatic Aberration / fringing in UV:

In extreme situations, in UV, the lens have a distinct fringing near the edges of the circle.

That can often be more or less cured by software in the postprocess.

The second UV sample below show such a situation with dark beams in silhouette against the UV-rich sky.

The third image show a partial section at 100%


Image samples:

UV:

post-150-0-37814500-1603632074.jpg

Filter: Omega 330W80 Improved

 

UV, Fringing:

post-150-0-27177700-1603724433.jpg

Filter: Omega 330W80 Improved

 

UV, Fringing 100%:

post-150-0-98871200-1603724155.jpg

Filter: Omega 330W80 Improved

 

VIS+NIR:

post-150-0-47277700-1603633510.jpg

Filter: ZWB3

 

NIR:

post-150-0-74535500-1603632119.jpg

Filter: long pass 800nm

 

Finally a full resolution 800nm NIR image:

(Double-click to see the full resolution image)

post-150-0-37497000-1603632168.jpg

Find the second bird against the sky!

 


Simplified transmission metric parameters

As graphs can be difficult to interpret and too big to be included in texts digested numeric values are needed to be used elsewhere.

---Suggestions to better parameter names are welcome---

 

TVISmax (%)

The highest transmission found in VIS (400nm - 700nm).

Gives a general idea of losses in the pass band.

 

T365nm (%)

Transmission at 365nm

A good indicator for how much the exposure time is affected for an UV shot.

Might be obtained with simpler tools than a spectrometer by comparison to a well known lens.

 

UVHalfC (nm)

The wavelength where the transmission at <400nm is 50% of TVISmax in a similar manner as FWHM for bandpass filters.

Observe this is not at 50% total transmission, making it more meaningful as it relates to the passband level.

 

UVKDSC (nm)

The wavelength at -3 stop at <400nm.

Useable mainly when compared against UVHalfC

Then it gives an idea of the steepness of the cutoff slope.

Kept for backward compatibility

 

It can in some cases be found in the Lens-Sticky.

For normal photography it gives an inflated view of the usable wavelength range.

Originally used by former member Klaus Schmitt in articles at Fotozones.

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On 10/25/2020 at 3:51 PM, Stefano said:

I think your ZWB2/ZWB3 image is UV+IR, not VIS+IR.

It was ZWB3 I used for that image.

 

The images from either filter alone looks rather close in colours after WB.

At least ZWB3 transmit enough blue and green to make a difference, just as in a BUG-vision stack that gives both UV- and VIS-components.

 

Without any IR-blocking filter it could actually be UV + VIS + IR, depending on the UV/IR ratio.

 

I used both filters that day and as raw images thy look very different.

 

Now when examining the images more closely I think the one above is taken with ZWB3. (UV + Vis + IR)

This is below with ZWB2 (UV + IR):

post-150-0-37886500-1603638632.jpg

 

Both WB against the walking path on the bridge.

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The Sunex is an interesting optic for those off-mainstream UV/IR images for sure. The idea of making labels for the various filters is neat, however, I mainly use the lens with cameras having internal filters so making adjustments for different focus is more appropriate for ym personal usage.

 

Thanks are extended to Ulf for a very clear and exemplary presentation.

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The Sunex is an interesting optic for those off-mainstream UV/IR images for sure. The idea of making labels for the various filters is neat, however, I mainly use the lens with cameras having internal filters so making adjustments for different focus is more appropriate for ym personal usage.

 

Thanks are extended to Ulf for a very clear and exemplary presentation.

I found it difficult to hit the exact infinity focus directly only using the camera as the magnification in live view was not good enough.

As the lens is so very sharp I like to be able to utilise all it's potential sharpness if possible.

It is also a quite quick method to reset the infinity focus after a more close up setting using the label.

Just a simple pencil line could be used for one type of filter only.

 

That is how I found the positions for the label.

There is no mark for the orange filter I showed above.

I used that only to make the putty-mount visible.

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In the near range, for which I found the SUNEX most useful, there is significant curvature of field in particular for UV. Not ideal, but once the issue is recognised it can be cast into alternte means of visual expression.
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This is very nice. I like the presentation format, Ulf. I don't think most members would be able to replicate the characterization of the lens that you did (with exception of Jonathan and David) due to lack of a spectrometer.
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Despite the obvious field curvature up close, nice images can be captured by the SUNEX. Here are two of my favourite flowers, indefatigable friends as any, and bringing hopes for a greener future :bee:

 

T201804213449.jpg

 

I1705043299.jpg

 

(last one cropped)

 

Hand-held with my Nikon D3200 (built-in Baader U). The dandelion shot, taken in sunshine, does show a bit more of the not-so-deep-UV response being slightly impacted by IR, plus the lens is prone to ghosting.

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I am surprised by its spectrum. Based on Birna's images I thought it dipped more into UV.

My Fujinon 2.8mm f1.8 I think might have better UV response. Problem is filters are nearly impossible to use with it. My best solution to date is to add a filter to the Pi camera and use it infront, as its a C-mount lens.

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David -

 

I think many of Birna's artistic images are really boosted for saturation when processed.

That seams to be a part of her personal image style.

A little bit of this also might be due to different camera sensitivities or Bayer responses.

 

My spectrometric measurements are really well calibrated.

I calibrated just before taking the transmission of the Sunex.

The average error for the 15+ peaks with my Ar Hg-calibration lamp was <0.35nm

 

My equipment for measuring lens transmission has been upgraded completely.

It ha a new better integrating sphere with proper internal barium sulphate surface coating.

 

I also got a new light source similar, but not identical to to the one Jonathan is using for his measurements.

He helped me to get that light source.

Thank you Jonathan!

 

My new light source differs from Jonathan's in that it has a wider wavelength range both into UV, VIS and NIR.

That gives me more steps for the measurement to be correct, but also gives me a possibility for a wider measurement range, spanning well into VIS and a bit into NIR.

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I have added these lens measurement metric parameters to the first post:

Now I need to get some sleep.

 

TVISmax (%) =

TVISmax@ (nm) =

T365nm (%) =

UVHC (nm) =

UVKDSC (nm) =

 

Their definition will then be better defined and I will motivate their purposes.

This post is just a notice of the coming change above

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I am using UHU Patafix.

You can cut it to a suitable length while still between the protective foils and bring a few lengths in the field if the used one needs to be exchanged.

I often use the same putty ring for several filter changes.

It is only the mount for UV that must be leakage-free all around.

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Ulf,

I never for a second doubted your spectrum. Just surprised by its outcome.

 

Yes post process is one of those things I need to do. Like sort and file my images correctly. Maybe why I am shifting to just straight out of camera Jpegs or InfranViewer resized images for posting here. I seem to be pushing too many projects into the future, that it may no longer matter anymore or even be possible. Thus why I stopped buying software. I still haven't even used the last photo software I bought.

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Ulf,

I never for a second doubted your spectrum. Just surprised by its outcome.

 

Yes post process is one of those things I need to do. Like sort and file my images correctly. Maybe why I am shifting to just straight out of camera Jpegs or InfranViewer resized images for posting here. I seem to be pushing too many projects into the future, that it may no longer matter anymore or even be possible. Thus why I stopped buying software. I still haven't even used the last photo software I bought.

Never thought you did. I just wanted to clarify for others.

 

My images, except for the big one, are screenshots directly from the RAW-viewer where I only can change gain and contrast.

The colour saturation is as from the camera.

 

I have noticed that Birna likes much punch in the chroma.

As we are mostly dealing with false colours that is naturally OK and maybe a heritage from the AIR-film's intense colour rendering.

 

I often try to enhance the colours a bit less.

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I just changed / enhanced the formatting of the first post.

Also added my definitions and some questions for the Simplified transmission metric parameters*:

 

So far I have not seen any suggestions for additions or improvements to this post as a template for similar posts for evaluating other lenses.

Please help me making this better by suggesting anything you are missing.

Maybe it is not applicable for this type of lens, but for other types.

 

I cannot have made the perfect format for such posts.

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Overall, I think you have given a well rounded and comprehensive review of the lens Ulf, in an easy to follow format. Good to hear that the light source is working out for you. I saw a second bird in your IR image, just above the tree to the left of center of the image :)
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Thank you Jonathan.

 

Maybe I should add information of some types of distortion like chromatic aberration.

 

I talked about sharpness, but with this lens there are no corners to investigate. :smile:

There is always a less sharp band close to the edge of these fisheye-lenses.

 

There is a third bird sitting on the lawn below the second one in the sky.

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I was wondering about chromatic aberration and whether you should include that, but is there a method which is applicable to UV (perhaps using a ruler at a shallow angle and looking for colours before and after the plane of focus)?

 

Oh I didn't look for a third bird :wink:

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Thank you Jonathan.

 

Maybe I should add information of some types of distortion like chromatic aberration.

 

I talked about sharpness, but with this lens there are no corners to investigate. :smile:

There is always a less sharp band close to the edge of these fisheye-lenses.

 

There is a third bird sitting on the lawn below the second one in the sky.

 

I just love how the center light flare looks like the moon coming up.

Great image.

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I was wondering about chromatic aberration and whether you should include that, but is there a method which is applicable to UV (perhaps using a ruler at a shallow angle and looking for colours before and after the plane of focus)?

 

Oh I didn't look for a third bird :wink:

 

Done, but only for edge fringing.

The depth of field goes from 0.5m to infinity so the transversal chromatic aberration will be difficult to find.

Please look again at the updated first post.

I already had an image that I think is reasonable suitable.

Do you agree that it is OK?

 

I also removed the TVISmax@ -parameter as I decided that it was not of much use.

 

I just found the third birdie myself.

Compared to my Sigma circular fisheye 4.5mm the Sunex is amazingly sharp.

The Sigma was such a disappointment.

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Good to know about the Sigma 4.5mm.

I was eyeing that lens as it nearly provides full circle on m43rds.

It could be just my sample, but I bought it new, not a used lens that could have seen some bumping around.

 

Sunex makes many different fisheye lenses that are not that expensive when sold on eBay.

It might be worth a try to check for UV-performance if you find any with suitable image circle:

http://www.optics-online.com/dsl_fisheye.asp

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My copy of the Sigma 4.5mm fisheye is a middle-of-the-road performer. Not bad, but is is prone to a lot of flare, and sharpness towards the periphery is so-so. It does focus very close, though.

 

C0905088482.jpg

 

A quick'n'dirty snapshot with the Sigma on my D200.I found no field notes as to the filter used here, it might have been an early Baader U (the one with the IR leak).

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