Mamiya Sekor 645 C 35mm f3.5 - haze inside the lens

[LittleAlex]

I own Mamiya Sekor 645 C 35mm f3.5. I had not been satisfied by it from the very beginning. There was some haze inside. So, I decided to clean it up. When I disassembled the last element (it consists from the single lens at the back, and the second element inside), I discovered, that all elements in the lens are perfectly clear, excluding only that internal element in the back component.

After closer examination I discovered, that the haze was inside of the component.

It is constructed from two lenses, glued together. Perhaps by Canada balsam. Or something other. I did hear that certain Mamiya Sekor lenses suffer from the problems with the glued elements. I myself was once on the rim to bay Mamiya 645 80mm f/1.9. At the last moment however I discovered that there were the problems inside of the two glued lenses back element. There was the very evident separation inside.

So, I am considering what might be done. Looks like to disassemble, and to re glue it will be quite impractical. To obtain the another one? Well, but if it not the bag, but the general feature with that lenses?

Does not look that it has to affect the general sharpness. Only it lowers the general contrast. So, on the digital back it might be marginally usable. Especially if to close down. I mean after rising up the contrast at the after processing.

But anyway it doesn’t look very good for me.

[LittleAlex]

After that unpleased discovery I decided to consider the possibility to obtain the second lens of that kind. But I worried much, that there might be se same trouble also and with the second sample.

To minimize that possibility, I decided to explore the market with the latest possible production examples in mind. Or – the AF lenses. Which unfortunately have the same optical formula. However, might be at the better condition yet. So I considered.

The AF samples are even some cheaper then preceding fully mechanical. I discovered several at Ebay. However, under the description of one of the items, the really honest seller mentions, that there is: “LIGHT HAZE UNDER THE REAR GLASS”. And gives the photo of it:



Which is exactly the same problem as in my own example!

So, I see it is really not the occasional bag, but the general feature with that lenses!

Which means that there is no way to obtain not the defective exemplar! And, so, it is completely useless to seek for it!

So, I had been pacified at the end in that my wish.

The problem is, that there really doesn’t exist any possible alternative in the system. I have incredibly good Zodiac-8 3,5/30mm lens, but it doesn’t really fills the hole, because it is fish-eye lens. Which puts it into the somehow different class.

So, it is the sad end of that story.

Still am not able to believe, that with the so professional system of so respectable brand were possible so abominable failures in the production quality!

[stevemark]

[LittleAlex]

[quote="stevemark"]

[stevemark]

I have been comparing a Minolta MD 2.8/35mm and my Mamiya Sekor C 3.5/35mm side-by-side by shooting into bright LED lights with a rather dark background. Of course with both lenses there's some flare/blooming aound the light sources, but the amount is nearly identical for both lenses.

Stopped down to f11, the Mamiya Superwide has some quite pronounced "blobs" and the Minolta doesn't - but that's simply beacuse the Mamiya has much more lenses (9 vs 5) and much, much larger glass surfaces than the Minolta (in fact five times larger area). Otherwise there's not more flare than with the Minolta.

Which means that practical shooting confirms that my Mamyia Sekor C 3.5/35mm doesn't have haze (it's the oldest, pre-N version).

S

[LittleAlex]

[lumens pixel]

Since you consider this lens a write off why not send the doublet to a professional for re cementing.

I have been told that schools in France like Sup Optique could do the job as student training if you get acquainted with someone. That could be a no cost solution.

[LittleAlex]

[LittleAlex]

Looks like that haze simply "just happens" from some production faults. For example - next sample:

"Mamiya 645 150mm f2.8 A - The glass is perfect other than slight haze around the very edge of the rear element"

https://ianbfoto.com/product/mamiya-645-150mm-f2-8-a-2/

So, not only with 35mm

My sample of the same lens doesn't have anything like that.

So, maybe the occasional slips with the lens glue consistence, or something like that.

[stevemark]