Disassembly – 7artisans 7.5mm F2.8 Fish-Eye lens

In this article I’m showing disassembly of the front area of 7artisans 7.5mm F2.8 Fish-Eye lens and sharing thoughts on its build quality. I’ve received this interesting lens sample about month ago from 7artisans, as a redirected customer return ( Thank you 7artisans! ). I was very curious why the lens got returned expecting some issue, and also interested to try another fisheye on Fuji (last one I’ve used before was quite good Samyang 8mm F2.8 UMC Fish-eye Mark II).

Fortunately it happened to be great and sharp 7artisans 7.5mm F2.8 lens sample so first I’ve spent few weeks shooting with it prior to the disassembly attempt. This lens is much sharper than 7artisans 12mm F2.8 , and personally it’s more fun to use it : ) First I’d like to share few impressions.

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It’s the only 7artisans lens I’ve seen so far that doesn’t have Serial Number. Another interesting thing – this 7.5mm F2.8 has exactly same built-in petal hood shape as 7artisans 12mm F2.8, and their front lens caps are interchangable (though 7.5mm front cap is soft plastic snap on type, while 12mm has petal shape fit cap).

Disassembly steps

I’ve noticed quite thick glue traces around the front black ring with letters, so decided to start disassembly from different point. You need to focus lens at 0.12m first, then unscrew three small bolts between the hood and focus ring.

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Once that is done, unscrew the front area CCW by holding the hood.

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You’ll get access to the aperture chamber and inner glass surfaces.

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Next step is a bit tricky, you need to push whole front lens section through the hood up to break up the glue connection. There is more gentle way to do that by rotating lens section CCW – it will unscrew it out from the front ring with letters. IMPORTANT: front ring with letters secures the front glass, so keep up directed up while unscrewing.

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I’ve pulled front glass element to check how it’s made – there is large blackened area on the opposite glass surface borders for reducing reflections. At this point you can completely disassemble front area optics.

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I’ve secured front glass element back by attaching front ring with letters and screwing it CW.

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At this point you can assemble front lens section back without the hood by screwing it CW inside main lens frame. Lens will look very strange without the hood : )

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I’ve put it on camera and took few test shots. Everything works like before the disassembly.

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Of course I’ve unscrewed front lens area CCW again, then focused it to 0.12m and attached the hood. Next step is to screw in CW lens section tightly. Finally you need to rotate hood to the optimal position and screw in three tiny metal bolts.

The lens is quite solidly built. I can see that aperture ring is connecting to the inner aperture lever through the large bolt you can find on the ring bottom area. Focus ring is very convenient and I very like the minimal 0.12m distance for close-up fisheye shots. I think it’s great decision to use soft snap-on plastic cap, it protects the front lens and also the hood itself from accidental hits. However I’ve noticed that cap become slightly loose after heating by direct sunlight. I’m personally not a big fun of using glue in the lens assembly (small bolt would work better), but it’s acceptable for budget lens.

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UPDATE (Sep 2018)

I took my 7artisans 7.5mm F2.8 lens for the next photoshoot and was unhappy to discover large white stains on the front glass. Looks like the factory glue from the lens hood got melted and distributed on top of the glass (I think my bag previously got exposed to warm Summer Sun light for few hours).

That large white stains affected the image forming fog-like spots (look at he shots bottom areas).

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Fortunately it was easy to clean out the glue without damaging the glass coating, it is dissolving in water.

I also noticed that some glue leaked under the front glass, so I’ve disassembled front area to clean front glass element and also removed all the glue remains from all parts. It helped to discover that 7artisans 7.5mm F2.8 lens hood consists of 2 parts. Basically when all the glue is removed, you can simply unscrew CCW the metal hood from its base.

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When the hood is unscrewed it’s more easy to disassemble the front glass area by simply unscrewing CCW the front metal ring with lens name. Secondly you can loosen three tiny black bolts around the lens hood base and pull it out from the lens.

I’m glad that all that glue got wiped out before it had chance to leak deeper into the lens. Lesson learned – don’t expose 7artisans 7.5mm F2.8 lens to the extreme warm conditions. Alternatively you can disassemble it, get rid of the glue remains, and assemble back. After that lens is safer for using in warm conditions, and I keep enjoying shooting with this Fish Eye after short maintenance.

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