Advice on my Setup

bakerbang · Post by **bakerbang** » Sat May 14, 2016 2:27 am

Hello I am new to this forum and I have a question about my set up. It is one I have recently put together using this thread

http://www.photomacrography.net/forum/v ... hp?t=12147

I have used a 40X Objective and I am wondering if perhaps the magnification is to large? The camera is a very old Nikkormat but has everything that is needed for this type of photography (inc shutter lock).

Light is passing through the objective and can be seen in the viewfinder but I cannot get any focus. The bellows is 160mm from film plane to lens plane and I have experimented with different lengths. I have also experimented with different distances of subject to lens.

Bellow are 2 images of my set up and one shows a close up of the objective any help would be appreciated.

Jon

Pau · Post by **Pau** » Sat May 14, 2016 4:31 am

Hi Jon, welcome aboard!

Some points you must be aware of:

* about the objective:
- the free working distance is extremely short (less than 1mm) so it's very difficult to have a subject both well illuminated and focused. Those objectives are designed for microscopes with typical biological slides (a transparent sample between and slide glass about 2mm thick and cover glass 0.17mm thick.
The subject must be flat and well parallel to the the optical planes. Without cover glass you'll suffer severe image degradation due to spherical aberration.
- the distance between the objective flange mount and sensor must be 150mm, not 160
- This is a simple achromat objective, the image center is focused at a different plane than the periphery.
- Very likely the objective image circle will be much smaller than the 24X36mm film, it is designed to make an image circle about 18 or 20mm diameter.

In short: this objective is really inadequate for macro work
All the former issues can be much less critical with a 10X Plan objective with enough working distance

* About the camera
- Despite MLU, the shutter function also produces a big amount of vibration, so you must use exposures over 1s or electronic flash to have a not blurred image
- The SLR camera viewfinder is inadequate to focus at this magnification
- Film is expensive and unpractical for an application that needs lots of testing and discarding.

In short, for this kind of work you need a digital camera with good live view, if you are short of funds for the project an used Canon EOS from 450 series upwards can be your best option.

* About the setup:
- Because the DOF is so small you imperatively need a precision focusing device. A microscope base could be the simpler option

Ichthyophthirius · Post by **Ichthyophthirius** » Sat May 14, 2016 9:18 am

Hi Jon,

I agree with Pau. An objective with lower magnification is an easier starting point, easier to illuminate the object, no need for a coverslip and more tolerant to changes of the tube length.

Look out for Nikon CF and CFN objectives for 160 mm tube length like

CF Plan 4/0.1
CFN Plan 4/0.13
CF Plan 10/0.25
CFN 10/0.30

which are widely used: http://www.photomacrography.net/forum/v ... hp?t=10661

If these are too expensive for you, you could try low-magnification Lomo Achromats for 160 mm like

8/0,20
10/0,25
10/0,30

which are also CDM-free (but have no anti-reflective lens coatings). Just the simple achromats, not the Lomo planachromats or apos, which have CDM!

Regards, Ichty

boomblurt · Post by **boomblurt** » Mon May 16, 2016 3:37 am

Welcome bakerbang

I am no expert but feel that one question worth asking is what do you want to photograph? 40x means that on the APS-C crop sensor, like the suggested Canons (which I use too), approximately 0.6mm (24mm/40) will fill the entire frame. The DOF will be razor thin and vibration will have to be dealt with somehow (flash?).

From experience may I suggest that, if possible, it's less frustrating to start with lower magnification (say, 1 or 2:1) and get the equipment, movement (focus block/rails etc) and lighting worked out and take it from there. It doesn't have to get too costly as there are relatively inexpensive solutions to most aspects, including lenses.

You've come to the right place as the people here are very knowledgeable, helpful and friendly.

bakerbang · Post by **bakerbang** » Mon May 16, 2016 1:44 pm

Hey Thank you everyone for all your time I really appreciate it!

I have a background in photography and for the last few years have been working as an artist mostly using 5x4 plate cameras see work at www.jon-baker.co.uk

I became interested in this guy http://www.laboiteverte.fr/nature-en-ph ... e-en-1909/ who in around 1900 fixed a microscope to the end of a plate camera and as his light source used a gas lamp!

I wanted to try something similar and looked into attaching a microscope to the end of my bellows and found your link
http://www.photomacrography.net/forum/v ... hp?t=12147

Attaching a microscope objective to 35mm bellows seemed a good way to start so I blindly bought the bellows and objective attachments and of course the objective. The Nikormatt is a great basic mechanical camera that allows bellows work which was why I chose it .

Pau do you think I would be unable to successfully focus with this camera? Would I get any image or will it just not show? Having shutter speeds of over a second is fine I am used to them being over 5 mins or 300 pops of the flash.

Hey Ichthyophthirius thank you for you advice do you think the below one will work? Has it got an RMS thread?

http://www.ebay.co.uk/itm/181912126013? ... EBIDX%3AIT

again thank you everyone for your advice, its really important that I can make the image on film so I am willing to work at it. Oh and im looking to photograph at least initially plant stems.

Best

Jon

Pau · Post by **Pau** » Mon May 16, 2016 2:48 pm

Your setup can work, Physics laws have not changed from the film days to now, although is not convenient for today standards.

+40 years ago I used to take BW pictures with a cheap manual SLR camera coupled to a monocular microscope, of course it's doable but is also true that I shortly abandoned it until digital photography became popular.

You can focus with the camera screen but not with precision, the screen is too coarse and optical focus aids don't work due to the very small effective aperture and you need lots of light. In many cameras the photometer will not be reliable.
Some SLRs have interchangeable screens and some makers (Olympus for sure, Nikon likely too) made special screens (transparent with a double cross reticle) to focus with microscopes. I never had this refinement.

But even being an expert photographer and not having economical constrains about shooting lots of film, all the caveats about the pictured objective still apply. I use the very same objective at my school lab microscopes and it isn't bad for its intended task and low price but as I explained it's only useful when mounted in a biological microscope with transmitted light and for not very exigent work.

If you plan to shot biological mounted slides the way is to couple the camera to a microscope to have the right illumination through the condenser, if you plan to shot opaque tridimensional objects you need an objective with long working distance to successfully illuminate it.

40X on sensor/film is a lot of magnification. Like others I must recommend you to begin with a 10X objective, not really easy but much more workable, later you can search for an adequate 40X

bakerbang · Post by **bakerbang** » Wed May 18, 2016 1:52 am

Thank you Pau

I have purchased an objective with a much lower magnification of x8 so i will see how I go from there

Thank you for all the advice

JB