Simple dslr adapter hack for budget scopes.

[LouiseScot]

I say 'budget scope' because it will likely only work with low end finite instruments like my Swift 380T. The idea came to me in a flash. I've been using one of the Ebay Chinese dslr adapters but I wasn't sure about it but didn't have anything to compare it with. Then I had the idea of simply using a telescope eyepiece knowing I had a stock 28mm 2" Sky Watcher eyepiece. This has two advantages - 1. They are cheap - you can pick one up for around £20 in the UK. Maybe even less elsewhere. They come bundled with some telescopes but if you use the telescope for imaging, the 2" EP goes in a box. Often resellers just split them off from the scope. 2. They have an M48 male thread so can screw directly into a M48 camera T-ring else to a T2 camera T-ring via an adapter. The lens end doesn't have any threads but it's easy enough to 3D print an adapter which slips over the lens end on one side, and fits into the trinocular tube at the other. My tube has a helical focuser attached to it and which has a 1.25" fitting with a brass compression ring.

So here are the parts:

EPadapter_parts.jpg (34.18 KiB) Viewed 3742 times

Camera on left, plus EP, plus adapter on right. The EP comes with a hollow metal section which screws on to the M48 thread and a rubber eyecup thingy. Both of those have been removed. The EP in the pic is facing the wrong way - my bad. The thinner end of the EP (about 40.5mm in diameter) goes into the wide part of the adapter. So I printed it to be a snug fit though it's easy to slide on or off. The 1.25" end of the printed adapter is also a fairly snug fit into my helical focuser and can be secured by thumbscrews if required.

Here it is in position:

Scope_EP_Adaptor.jpg (55.51 KiB) Viewed 3742 times

I'm not guaranteeing optical quality but I posted a couple of images using it in the Pictures and Videos section and at the end of the 'Naphrax vs Pleurax' etc. thread. II think it's comparable to the Chinese dslr adapter but was actually a lot cheaper for me to make!

Hope this might be of interest/use to anyone with a Swift380T or similar Trinocular.

Oh, here's a quick pic of a whole (diatom strew) field reduced by 70%:

Pleurax1100d_40x_EP1_all - Copy.jpg (88.95 KiB) Viewed 3742 times

Louise

[LouiseScot]

I should probably have posted this under 'home made microscope adaptions' - maybe a Mod could move?

Thanks

Louise

[MicroBob]

Hi Louise,
thank you for posting your camera adaptation! There are quite a few people who buy similar microscopes and already have a Canon DSLR so this will be interesting for them. There are also many beginning microscopists who have a background in astronomy and might even have such an astro eyepiece.
Your sample image has some brightness fall off towards the edges and the sharpness towards the edges is not great. This may just be a result of the non-planar objectives. Can you post 100% crops from the center and the corners when you focus just on this area? Under ideal circumstances a simple acromat gives a nice image in the edges of the image when focussed there.
Does your adaptation cover the whole image you see in the eyepieces (cut to rectangular frame)?

Bob

[LouiseScot]

Hi Louise,
thank you for posting your camera adaptation! There are quite a few people who buy similar microscopes and already have a Canon DSLR so this will be interesting for them. There are also many beginning microscopists who have a background in astronomy and might even have such an astro eyepiece.
Your sample image has some brightness fall off towards the edges and the sharpness towards the edges is not great. This may just be a result of the non-planar objectives. Can you post 100% crops from the center and the corners when you focus just on this area? Under ideal circumstances a simple acromat gives a nice image in the edges of the image when focussed there.
Does your adaptation cover the whole image you see in the eyepieces (cut to rectangular frame)?

Bob

Hi Bob

Yeah, the illumination and focus does fall off in the corners but I think it did anyway. It may be that it's just that the centre is over bright - I'll have to do some flocking as there may be internal reflections. The Swift objectives are only achromats, not plan achromats. I'd say the adapter shows about 60-70% of the whole field (18mm ocular). The eyepiece could be used with any camera for which a T-ring is available. Of course, there are other, much higher quality eyepieces available but at a corresponding higher price, and most aren't suitable for repurposing though there are always opportunities to be creative. I'm personally not bothered about fall off in the corners since I would almost always be interested something in or near the centre.
I've done some crops with a 40x objective but at 100% all my dslr images come out blurry anyway. I learned a short while ago not to attempt to show images at 100% camera resolution. 50% is good.

This is the EP, as sold:

https://www.rothervalleyoptics.co.uk/sk ... d-kit.html

Anyway, here is a whole frame brightfield (resized to 30%) and 100% crops, 40x with slight brightness/contrast adjustments:

Pleurax_EP1_830pc.jpg (52.33 KiB) Viewed 3681 times

centre crop:

Pleurax_EP1_centreCrop.jpg (46.32 KiB) Viewed 3681 times

Bottom left crop:

Pleurax_EP1_botLeftCrop.jpg (45.55 KiB) Viewed 3681 times

Lower right crop:

Pleurax_EP1_lowerRightCrop.jpg (57.94 KiB) Viewed 3681 times

Louise

[MicroBob]

That looks quite good to me. Just a bit of colour fringes in the corners, nothing really serious. And diatoms are a fairly critical test.
For wide flat objects you could use photo stacking to bring everything in focus without having plan objectives.

Bob

[LouiseScot]

That looks quite good to me. Just a bit of colour fringes in the corners, nothing really serious. And diatoms are a fairly critical test.
For wide flat objects you could use photo stacking to bring everything in focus without having plan objectives.

Bob

Thanks. Yes, I plan to do some focus stacking when I can find the time - not enough hours in the day!
Louise

[LouiseScot]

Hmm... On further inspection... The astronomy EP does produce quite a lot of 'pincushion' distortion towards the edges. That's to be expected with a cheap EP. An alternative would be an orthoscopic EP but they are quite expensive - would defeat the object. I've also tried with an actual Swift 10x/18mm EP. They are quite good but the fov is quite narrow. I suppose, at the end of the day, the Chinese dedicated dslr adapter is still the best. Even so, that also has some pincushion distortion. Maybe a 10x microscope eyepiece with a 22mm field would be better, but I don't have one to try. Again, can be quite expensive. I've ordered a different 25mm astro eyepiece which is supposed to have high contrast and low distortion just to try. If it's not as good as, or better than, the dslr adapter I can always use it on a telescope and will be better than any of the ones I have

Louise

[LouiseScot]

If anyone is interested, Oliver reviewed the Chinese dslr adapter a year ago:

https://www.youtube.com/watch?v=Ju8rgeJr3bI

Louise

[Hobbyst46]

If anyone is interested, Oliver reviewed the Chinese dslr adapter a year ago:

https://www.youtube.com/watch?v=Ju8rgeJr3bI

Louise

For an old finite optics microscopes in which spatial and color corrections are done in both the objective and eyepiece, I doubt that those DSLR adapters (when they include a lens) would perform OK. Perhaps they are specifically optimized to perform on Olympus microscopes like the one demonstrated by Oliver. I also wonder how they perform with a mirrorless camera (is there a parfocallity issue).

[LouiseScot]

If anyone is interested, Oliver reviewed the Chinese dslr adapter a year ago:

https://www.youtube.com/watch?v=Ju8rgeJr3bI

Louise

For an old finite optics microscopes in which spatial and color corrections are done in both the objective and eyepiece, I doubt that those DSLR adapters (when they include a lens) would perform OK. Perhaps they are specifically optimized to perform on Olympus microscopes like the one demonstrated by Oliver. I also wonder how they perform with a mirrorless camera (is there a parfocallity issue).

Hiya
I did say in the original post that the EP hack is only suitable for budget, finite microscopes like the Swift380T, for example. Similarly for the Chinese Dslr Adapter which do include lenses and an adjuster for field of view. The dslr adapter is sold with either Canon EOS T-rings or Nikon ones. It would be easy enough to increase sensor spacing for mirrorless. I have a Fuji X-T30 mirrorless that I'll be trying at some point. It should attach via a Fuji X to EOS adapter which I've got The dslr adapter works ok on the Swift380T with a Canon 1100d.

Louise