DIY lens - question on image circle

A 4" lens barrel and board arrived today - anyone guess what it actually is?

Also some 110mm lenses arrived, they are 4 dioptre and are over 4" wide - I will be getting a wider barrel and board made up to fit them, they are 4 dioptre lenses (although they are double convex so not ideal) but I will try and see what they are like stopped down

Steve also very kindly sent me some bellows, the front of a larger set has a 4" hole which I will perhaps look at building a front standard for as well.

Things seem to be progressing quite well so far, I will see how much progress I can make on Saturday, hopefully the macro slider rail will arrive soon so I can attach the standards etc.

Just had a quick test with the lenses, due to the MASSIVE lens circle these things seem to generate the 5x4 area only really gets the centre of it meaning that its actually quite sharp and clear which is what I was aiming for - if they were smaller and of this design then the 5x4 area would have been nearer the edges which would have meant a lot of imperfections, will be interesting to stop the lens down.

250mm f2.2

125mm (ish) f1.1 - its a tad out of focus due to having to hold 2 lenses together and shoot using a manual lens lol but you get the idea, still quite a good image, slight bit of distortion.

m1tch said:

A 4" lens barrel and board arrived today - anyone guess what it actually is?

Click to expand...

Part of a dryer vent?

MattKing said:

Part of a dryer vent?

Click to expand...

Close, its a wall bracket for ducting, smallest it comes in is 4", seems great for a DIY lens build, its even got notches inside which could hold the lens in place etc

I have the basic parts for the larger lens, just went out to buy the barrel:

Rubber gasket - unfortunatly the lenses don't hold in at the moment as the barrel is 110mm and so are the lenses, the seals are slightly larger but can probably sort out by packing out the sealing surface

There is a lip in the centre (there were some without) but I will use this to hold the waterhouse stops in the centre

Needs a clean but this is just a test lol

150mm f1.3 - it looks amazing on the ground glass, it looks almost 3D

I really need to use my other camera lens but this is it stopped down using some cardboard - guessing around f15

This lens will be called the Q1, in honour of the Carl Zeiss super-Q 40mm f0.33 lens, the Q stood for "Quatsch" translation 'Nonsense' lol

http://thedreamwithinpictures.com/b...igantar-40mm-f0-33-the-fastest-lens-ever-made

Image circle example

I then free lensed it with the NEX-3, this is ISO 200, 1/160, 150mm f1.3 - this is on a crop sensor so its somwhat enlarged - bicycle across the way

My 82mm close up lenses have arrived, you can see the 52mm lenses on the left, the 82mm lenses in the middle and the 110mm lens on the right.

Here is the crazyness that is the +8 lens, means its a 125mm lens so an f1.6 lens, image circle is good and the image is brighter compared to the 52mm lens version (which is why I got this size to give some extra stops of light).

There is also a +3 filter which is a 330mm lens at around f4, I just focused it on the wall, the image circle is around a foot, maybe larger lol

What I am tempted to do is to use the 4" (100mm) wall duct and sleve a filter(s) inside it giving me manual focus and use the bellows on the larger 110mm lens. I might just look at fitting these 82mm lenses with some waterhouse stops and add a lens board so I can use the speed graphic focal plane shutter.