R apo 180/2.8 ROM variations

[Alon]

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Hi Alon!

I have some sample picture on Fredmiranda.com of R Apo 180 f2.8 when stop down to show "Ninja star". Is it the cause of ninja star on bokeh?

Thanks!

 

IMG_1764.JPG

 

Yes, it is.

[masjah]

Looking through my v2, its aperture blades exhibit no such "Ninja" effect, though I have seen it before (on a 280/4 Apo R) and was assured that for this lens it is a normal property of the aperture blades. You learn something new in the way of jargon every day!

Edited September 3, 2017 by masjah

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[Alon]

Looking through my v2, its aperture blades exhibit no such "Ninja" effect, though I have seen it before (on a 280/4 Apo R) and was assured that for this lens it is a normal property of the aperture blades. You learn something new in the way of jargon every day!

 

 

Yes, the 280/4 APO does have Ninja blades up to f5.6 and turns into a poly past f5.6 and fades away past f16.

[Leicaiste]

When I compare the Apo-Summicron 90mm in M (1998) and R (2002) Mounts, the R has 8 aperture blades and the M has 11, but strangely enough, the apertures on the R are rounder, except at f/16.

[bencychin]

V. 1 modified to accept the 1.4X extender R has the rearmost element recessed further into the lens.

 

At f/2.8 the aperture blades are rounded.  At each half-stop thereafter through f/6.8, the aperture blades have to varying degrees some "ninja star" shape.  At f/8 the blades take a shape similar to the above photos.

 

I have seen no evidence of the aperture shape in any specular highlights rendered since the conversion.

 

A further change made to my copy is that it has a steel grey aperture ring, possibly because parts were in short supply.

 

Thanks for solving many of my long standing doubts.

 

My copy seems like a mod copy of Apo 180 f2.8 v1 (ser: 3816xxx, order no: 11273).

It has the electronic contacts at the rear flange of the bayonet mount, but I have never tried it with either 2x or 1.4x extender (as I don't have it).

 

How do I determine if it can fit?

Thanks for your sharing.

 

Benedict

[masjah]

Thanks for solving many of my long standing doubts.

 

My copy seems like a mod copy of Apo 180 f2.8 v1 (ser: 3816xxx, order no: 11273).

It has the electronic contacts at the rear flange of the bayonet mount, but I have never tried it with either 2x or 1.4x extender (as I don't have it).

 

How do I determine if it can fit?

Thanks for your sharing.

 

Benedict

 

 

Benedict, I'm not sure exactly what you are unsure with what (sorry if I'm being a bit slow here!). You've got a ROM 180/2.8 lens, so it would fit OK on the 2X extender (and I would only consider the 2X Apo extender, not the earlier non-Apo version). In fact I would also use a ROM Apo extender with an R8/R9. Whether or not it fits on the 1.4X Apo extender (which is only non-ROM) depends simply on whether or not you have a modified earlier version, or the very latest version, but you suggest that yours is modified, so would be OK. If you're not completely sure whether it is in fact a modified example, you'll need to check whether the inner glass element is sitting deeper into the lens. Best way would be to inspect it with a 1.4 extender to see if there looks to be enough clearance, or else to compare it with a known later version lens.

[Steve McGarrett]

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Post a picture of the rear end of the lens...

[bencychin]

Post a picture of the rear end of the lens...

Will do.

 

I will get a picture of the rear end of the lens.

 

Thanks for good suugestion

 

Benedict.

[bencychin]

Benedict, I'm not sure exactly what you are unsure with what (sorry if I'm being a bit slow here!). You've got a ROM 180/2.8 lens, so it would fit OK on the 2X extender (and I would only consider the 2X Apo extender, not the earlier non-Apo version). In fact I would also use a ROM Apo extender with an R8/R9. Whether or not it fits on the 1.4X Apo extender (which is only non-ROM) depends simply on whether or not you have a modified earlier version, or the very latest version, but you suggest that yours is modified, so would be OK. If you're not completely sure whether it is in fact a modified example, you'll need to check whether the inner glass element is sitting deeper into the lens. Best way would be to inspect it with a 1.4 extender to see if there looks to be enough clearance, or else to compare it with a known later version lens.

Sorry i am not so precise with my questions.

I use it on an SL 601 body. So i think ROM is of less value to me.

I prefer 1.4x so i can still take photo at F4.0.

 

By my looking, the rear glass element is quite deep into the lens.

But i dont have any extender with me, so cannot try to match it.

 

I will take a picture of the rear end and post it.

Thanks for your advice.

 

Benedict

[bencychin]

I attach the photo of the rear of the lens.

Apologies it is taken with ipad camera for ease of sending.

 

Benedict

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[bencychin]

I attach the photo of the rear of the lens.

Apologies it is taken with ipad camera for ease of sending.

 

Benedict

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[masjah]

Benedict, from the photograph, it's a bit difficult to say one way or the other whether your lens is modified or not, but there are two white spots that look like reflections from the rear surface of the rear element , the larger of which gives the impression of the element being quite near the rear of the lens but this may be an illusion. Can you estimate how deep the rear element is within the throat. (Maybe dangle a bit of cotton thread down into the lens and measure it?

[Steve McGarrett]

Or you can simply make a red mark on the black tube in the picture to help us understanding where the rear element really is, because it's impossible to say from that image...

[bencychin]

Benedict, from the photograph, it's a bit difficult to say one way or the other whether your lens is modified or not, but there are two white spots that look like reflections from the rear surface of the rear element , the larger of which gives the impression of the element being quite near the rear of the lens but this may be an illusion. Can you estimate how deep the rear element is within the throat. (Maybe dangle a bit of cotton thread down into the lens and measure it?

Benedict, from the photograph, it's a bit difficult to say one way or the other whether your lens is modified or not, but there are two white spots that look like reflections from the rear surface of the rear element , the larger of which gives the impression of the element being quite near the rear of the lens but this may be an illusion. Can you estimate how deep the rear element is within the throat. (Maybe dangle a bit of cotton thread down into the lens and measure it?

John and Steve,You have keen observation. So naive of me not to at least try to measure down the rear element!I simply did a cotton bud test. It is now evident it is just 1.5 cm deep.The cotton bud photo tells all.Sorry to have trouble you all with all my questions.Never too old to learn new tricks.Many thanks to you both.Have a pleasant weekend.Benedict.

Welcome, dear visitor! As registered member you'd see an image here…

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[Steve McGarrett]

I should check mine to be 100% sure, but it looks to me like a standard v1 (ie. no 1.4x extender compatibility)

Edited November 11, 2017 by Steve McGarrett

[Michael Geschlecht]

Hello Everybody,

 

If the rear element is a convex lens then the depth at the edges will be MORE than at the center.

 

That is: The center of the element will be CLOSER to the 1.4X.

 

It is better to measure from the highest point where the glass element is CLOSEST to the back of the lens.

 

Best Regards,

 

Michael