Using 10x objective with Sony A7rii full frame

AlisonP · Post by **AlisonP** » Fri Jan 31, 2020 2:03 am

Hi folks, I am an experienced macro photographer and want to try extreme macro photography with a 10x microscope objective. I have read many of the excellent postings in this forum on microscope objectives. Several of them I have read many times to try to understand all the details. Thanks to all you dedicated extreme macro photographers for sharing all your information.

I'd like to get a little additional information and recommendations before I purchase the objective to be sure I have what I need.  For background -- my macro photography subjects are Myxomycetes and very small fungi. Myxos, though, are my passion. You can see my photos online at https://www.instagram.com/marin_mushrooms/

I use a Sony A7rII with the Sony 90mm macro lens for 1:1. Most of the time I have the Raynox 250 added to that, which gets me to about 2.5:1. I focus stack manually in the field for virtually all of my photos with this lens combination. I also have the Laowa 25mm 2.5-5:1 lens which I use in a home studio; with this lens I use the Stackshot automated rail for focus stacking.

I will purchase either the Nikon 10x CFI plan achromat NA 0.25 or the Mitutuyo 10X /0.28NA Plan Apo Infinity-Corrected Long WD Objective (Edmunds Stock #46-144). Big difference in price, but I am willing to purchase the Mitty if it indeed gets significantly higher sharpness, and also because of the significantly longer working distance.

Here are the questions I am hoping someone can answer:

1. Will both of these objectives cover a full frame sensor? Or would I have to use my camera in APS-C mode? I don't mind a little vignetting because I can crop to a different aspect ratio which I frequently do anyway.

2. I have at hand and can use as the tube lens for the infinity objective the Canon 70-200mm f4. I use a Fotodiox adaptor to connect that lens with my Sony and have not had any problems with that. Because the Fotodiox adaptor adds a little length to the "tube", would I then set the Canon to a little less than 200mm to account for the length of the Fotodiox adapter? If I use this lens then my setep would be
Sony A7rII + Fotodiox adapter + Canon 70-200mm f4  + adapter ring to mount objective onto 70-200mm lens + objectiveIs that correct?

3. Would it be better to use the Raynox 250 as a tube lens? I don't have but can purchase the Raynox 150 if that is better.I have seen Rik's posting on how to attach this to a camera here: https://www.photomacrography.net/forum/ ... hp?t=35350

Thank you in advance for answers to my questions and any help you can offer.

Adalbert · Post by **Adalbert** » Fri Jan 31, 2020 2:55 am

Hello Alison,
Welcome to the forum!
I would recommend you the Mitutoyo M Plan Apo 10 / 0.28 and Raynox DCR-150.
If you wanted to push down you could change DCR-150 to the DCR-250 in easy way, because they have the same mount.
BR, ADi

Macro_Cosmos · Post by **Macro_Cosmos** » Fri Jan 31, 2020 3:52 am

Welcome to the forum!

1. The Mit 10x which I have the exact model you linked to does cover FX with ease. The Nikon should as well, but I don't have one. The Mit is excellent.

2. The setup would be:
a7r2 - Adaptor - Canon 70-200 F4 - Adaptor (67mm > M26x0.706 if you're going with the Mit) - Objective lens

You need to put the lens on a tripod, use liveview to focus at a very distant object, maybe a tree or the moon in the sky should work too.

I would recommend the Raynox DCR-150, it works very well as a tube lens and can be a great add-on for your 70-200 as well. There's lots of posts on adapting the Raynox. Wemacro offers a set of adaptors that makes this process very easy... however it might not be possible to get it as of now due to China's virus outbreak. I'll ask William.

3. Yes I would recommend the DCR-150. The DCR-250 works as well, though I don't have experience with it.

Rafcamera based in Russia has an assortment of adaptors.
This is for your 70-200 lens:
https://rafcamera.com/adapter-m67x0-75m-m26f
The thread pitch is 0.75 rather than 0.706, but it will work.

Nice shrooms! They look very tasty...

I'll give you a follow.

ChrisR · Post by **ChrisR** » Fri Jan 31, 2020 5:44 am

Hold on folk, surely the Canon 70-200mm f4 would cause some vignetting on full frame?? I don't have one, but...

The stronger DCR-250 used as a tube lens for ~6.25x would as well, on full frame, I think.

Even if you don't get image cut-off, things do degrade when you're outside the image circle the manufacturer intended.

Good news is that there are good, cheap 4x options available, like the Nikon BE ($50 ish). The zoom would likely still cause cut-off on full frame, though,

Getting a well priced, working-as-new used Mitutoyo is a lottery. I bought 3-4 baddies before a keeper. The first one I still have, because I had nothing to compare it with. Without (someone else) comparing the others with a known good lens, I don't know where I'd have been.

The BEs may make good sense - see here: https://www.photomacrography.net/forum/ ... hp?t=27205

Macro_Cosmos · Post by **Macro_Cosmos** » Fri Jan 31, 2020 5:52 am

Not sure about the F4, that's right. The F2.8 I heard is pretty decent.
My 70-200 F2.8 FL from Nikon has rather heavy vignetting too, however the 200 F4 ais is very good, despite also being a stop slower.

DCR-150 is worth it, it's usually $60 or something.

Lou Jost · Post by **Lou Jost** » Fri Jan 31, 2020 5:59 am

I'd go with the Mitutoyo, bought new. The working distance is very useful and it has better coverage on FF than most other objectives.

because the Fotodiox adaptor adds a little length to the "tube", would I then set the Canon to a little less than 200mm to account for the length of the Fotodiox adapter?

No, that's doubly wrong; the adapter is not adding any length to the designed lens-to-sensor distance of the Canon, it is equalizing the length to the proper distance for infinity focus with that lens; the Sony mirrorless camera has a shorter flange to sensor distanace than a Canon camera.

And even if it did, you wouldn't change the focal length to correct that, you would change the focussed distance.

People on the forum have used this lens as a tube lens and have been happy with it at 200mm, but most have used it on APS. You should do a search to read people's experiences with it.

rjlittlefield · Post by **rjlittlefield** » Fri Jan 31, 2020 10:15 am

1. Will both of these objectives cover a full frame sensor?

Yes, both objectives cover full frame, no problem there.

But I recommend the Mitutoyo also. In addition to more WD and sharpness, it has much less longitudinal CA. The Nikon has a lot of blue/purple haze, especially in OOF regions. This is diminished but not eliminated by focus stacking. I will repeat the concern about used Mitty's. I still have a bad 10X that I received before I knew how good they could be. I replaced it with a new Mitty from Edmund Optics and have been very happy since.

--Rik

AlisonP · Post by **AlisonP** » Fri Jan 31, 2020 10:08 pm

Thank you all for your very useful and informative, and quick, replies! Very helpful! I have been following threads in this forum for some time, and am so impressed by the amount of detailed help that people give each other.

I was leaning towards the Mitty and will go ahead and order that. I will try that with my Canon 70-200mm first since I need only get the adapter for the Mitty to the lens to test this out. If I am not satisfied with those results, I will go ahead and get the Raynox 150 (which I had been thinking about anyway to add to kit for use in the field).

I have done a fair amount of 5x work, and am excited to try my hand at 10x to reveal more the beauty of the delicate structures of Myxomycetes.

Again, thanks everyone very much!

Adalbert · Post by **Adalbert** » Sat Feb 01, 2020 3:27 am

Hello Alison,
Good choice :-)
I have been using the CANON EF 70-200L f4 as a tube lens for the long time:

Firstly with an expensive adapter from RAFCAMERA then with the cheap step-down rings from China:
67->52->30->26 for Mitties
67->58->25 for Nikon Lu Plan
67->52->37->RMS for Nikon BE Plan
BR, ADi

Lou Jost · Post by **Lou Jost** » Sat Feb 01, 2020 5:20 am

Adalbert, at what point in the 70-210mm zoom range do you start getting vignetting with the Mitutoyo 10x?

Adalbert · Post by **Adalbert** » Sat Feb 01, 2020 8:31 am

Hello Lou,

So, I have just tested for you :-)

With the FF-camera (6D) starts vignetting close to 200 but it is well visible at ca. 180 and at 100mm gets the diameter 24mm (close to the whole height of the sensor).

With the CROP-camera (M3) starts vignetting close to 135 and at 70mm gets the diameter 20mm (close to the whole width of the sensor).

The quality of the CANON EF 700-200L as a tube lens is the best I have ever tested but I have switched to the Raynox DCR-150 because it is not as expensive as CANON :-)

BTW, CANON EF 100L macro is an excellent tube-lens too (but pushed down divided by 2).

BR, ADi

Lou Jost · Post by **Lou Jost** » Sat Feb 01, 2020 9:01 am

Thanks very much for testing, Adalbert!!! I am using FF so those are discouraging results, but not unexpected for a zoom. Just to be sure, the FF corners are not at all vignetted at 200mm? That is an excellent lens.

Does the 100mm macro vignette in the corners of FF?

Adalbert · Post by **Adalbert** » Sat Feb 01, 2020 12:51 pm

Hello Lou,
Yes, EF 70-200L is not bad (for FF :-)
But EF100L macro gets a diameter a little bit smaller than 36mm (some vignetting for FF)
BR, ADi

Chris S. · Post by **Chris S.** » Sun Feb 02, 2020 11:47 am

I've PM'd Alison, offering to test a used Mitutoyo objective for her if she wishes.

--Chris S.

AlisonP · Post by **AlisonP** » Mon Feb 03, 2020 11:58 am

Thanks again gentlemen fo all the info. You guys rock!

Adalbert says the Canon 70-200L lens is the best tube lens that he has tested. I am happy to hear that as I already have that from my time as a landscape photographer. I have just ordered the Mitty and the adapter.