WTB (UK) Century precision optics 4+ diopter

[Pitufo]

Anyone?

[Photomicro]

Anyone?

I don't have one of these, but I do have an Olympus MCON-35, a high-quality close-up attachment lens originally for the Olympus E-10 camera. It is fitted with a 62-mm front thread and is multi-element achromatic. The focal length of the MCON-35 is 35 cm (according to Olympus), which translates into +3 diopters.

Any use?

[Pitufo]

Hi Mike

That was quick, thanks. Yes, it sounds interesting.

My idea is to mount it on an Olympus 60mm macro lens (46mm) for use with very small subjects with bracketing.

Would you like to PM me the price? I will see if I have the appropriate step rings.

Cheers,

John

[Yawns]

4+ on a 60mm lens will probably give you a residual gain in magnification... a common m43 set of tubes (10+16) will work better, I think

[Yawns]

I have the same equipment ( I presume) and I just did some bold quick measures...
and tubes don't add more glass to the system.

[Pitufo]

Thank you very much Yawns for taking the time to do the comparison.

That does look good.

If I understand correctly, the extension tubes sit between the camera and the 60mm lens?

Does this still allow all the lens functions (focus, bracketing, etc) to work normally?

I'm using an E-M5 mk II.

Cheers,

John

P.S. This kind of thing https://www.ebay.co.uk/itm/Pixco-Auto-F ... SwRLZUKOjt

https://www.amazon.co.uk/Viltrox-Extens ... 1-fkmrnull

[Yawns]

Yes, that kind of thing ...

Yes, they sit between the camera and the lens,



as long the tubes have contacts and the camera / lens can communicate everything works just the same (some very cheap versions don't have contacts)

[Pitufo]

Brilliant, thanks

They look well worth a try. Easy to get hold of too.

P.S. Spoke too soon, they all seem to be Chinese sellers and I have a deadline..

[Yawns]

yep.. any 20 pounds will get you a set of tubes... not a big loss if you dpn't like it...

just be very careful about dust and keep the tubes very clean (mine in the picture are in a mess)
keep them dust free and give them a blow with the camera blower before using it.. they drag dust to the sensor if not very clean. If the set doesn't comes with caps... buy a cheap extra camera body cap and a lens cap, to keep the tubes always closed..

[Lou Jost]

tubes don't add more glass to the system

That's exactly why this is likely to be a bad solution. Lenses like these are optimized for a particular flange-to sensor distance, and using extension tubes takes them away from their design point.

It is true that adding more and more extension will give you more magnification than a given diopter, but this is done at the cost of increased effective aperture and diffraction blurring. If pitufo only needs a small boost in magnification, a high-quality diopter will be better than extension. It does not decrease the effective aperture, so it doesn't increase diffraction, though it might introduce other problems.

I have tested several diopters, including the Raynox and the +4 Precision Optics, on this Oly 60mm lens. I found the +4 Precision Optic diopter to be the best of the ones I tested. There was minor degradation near edges, but it was very usable.

If more magnification is needed, I recommend buying one of those extension sets, but instead of using it as directed, take it apart and make a wired reversing ring out of it, and use your 60mm lens in reverse. This is very very good.

http://www.photomacrography.net/forum/v ... highlight=

[Pitufo]

Thanks Lou.

My goal is increased magnification in the field for myxomycetes, so the extension tubes seem worth a try, especially as they are cheap and light.

Mike has also offered a very reasonably priced +3 diopter Olympus MCON-35, so I will probably add that to the equation also. The change in diameter 46mm to 62mm sounds a bit drastic however...

P.S. Thanks for the link to the reversed set up. Impressive DIY!

[Yawns]

That's exactly why this is likely to be a bad solution.

Ok I'm sorry for that silly remark ...

[Lou Jost]

Sorry Yawns for my tone, your comment is not necessarily silly.

Pitufo, what magnification do you need? If your subjects are shallow in depth, and if you don't mind slight corner vignetting, you can use the 60mm or 75mm or higher Oly with a low-power objective, and automatic focus bracketing. This works well in the field, creating almost-instantaneous stacks. But the focus range is short; the 60m gives the most focus range but at the cost of more vignetting. Some of that vignetting can be reduced using the Photoshop correction tools for vignetting.

[Pitufo]

Thanks Lou.

I think around 1:1 - 3:1 would be good.

I have quite a few 4x objectives kicking around but nothing lower than that.

It did consider getting a longer high-quality Oly zoom that someone was using a tube with good results but I couldn't really justify the price.

P.S. I am soon to be the proud owner of both a +3 diopter and some extension tubes, so that should give me plenty to play with for a while!

[Lou Jost]

Don't forget that the 60mm lens lowers the nominal magnification a lot.

I suppose you mean that you want FOVs between 6-17mm?

The reversed Oly does really well in that range. Unfortunately the +4 diopter will not get you anywhere near 3x.