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on Jun 2, 2019 8:31:14 GMT
Posted: Jun 2, 2019 8:31:14 GMT
Hi
I recently purchased a Yashica 500mm F8 . When I mounted it on my Yashica FR, I notice in the viewfinder aperture scale it read F1.4. I also noted that the metal tab wasn’t as far round as the metal tab on my 135mm lense. Any ideas?
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on Jun 2, 2019 13:13:42 GMT
Posted: Jun 2, 2019 13:13:42 GMT
The 500mm f8 mirror has a fixed aperture. There is no need for an f-stop tab. Perhaps the f1.4 in the read-out is simply a default setting.
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on Jun 2, 2019 17:23:55 GMT
Posted: Jun 2, 2019 17:23:55 GMT
The 500mm f8 mirror has a fixed aperture. There is no need for an f-stop tab. Perhaps the f1.4 in the read-out is simply a default setting. After taking a quick look at some eBay listings for Yashica 500's (I don't have one to check it), they do show a max-aperture tab next to the rear mounting ring. At least on the version shown, it was the flat L-shape style, with 2 screws to attach it. Here's a link to an old topic where I posted a pic of the different tabs/posts/levers and their positions and functions. The tab type on the right-hand lens shown, is the same/flat tab I see on the 500's. If there is/was no tab, then yes, it would misread the aperture and could throw off metering, while a film body see's it as a wide open f/1.4... and depending on the body it's mounted on, it might even see it as a f/1.2. The metering would otherwise rely on the current aperture position provided by the sliding lever moved by the aperture ring on most lenses, but the fixed f/8 wouldn't ever have one of those anyway. I don't currently have any lenses that are without their aperture tab and/or lever to test whether the metering would absolutely fail, so it might boil down to what body it's on, and how it deals with stop-down metering - since that's the same scenario as a fixed aperture lens. None of this matters if it's adapted to a digital body as a manual lens, of course. However... If the mount assembly has the 2 holes where a tab should be, you might be able to transplant a tab from another lens - but - be aware that the position is critical and it has to be positioned precisely enough to get the body to see the right aperture when it's engaged with the tab. There are slots on the foot of the tab so it can be adjusted, so it's just a lot of on-the-camera/off-the-camera juggling to get one adjusted. I've only adjusted an existing tab once, it it was very frustrating to do, but it just takes patience and persistence. |
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on Jun 2, 2019 20:03:01 GMT
Posted: Jun 2, 2019 20:03:01 GMT
I dug out a few more 500mm reflex pictures to get a better look, and what I thought was the L-shaped tab is actually a T-shaped tab. Those may be in shorter supply as replacements than the L-shape
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on Jun 3, 2019 22:37:12 GMT
Posted: Jun 3, 2019 22:37:12 GMT
WOW a 500mm f1.4. Sign me up!
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on Jun 4, 2019 3:21:10 GMT
Posted: Jun 4, 2019 3:21:10 GMT
WOW a 500mm f1.4. Sign me up! I'd consider signing up too, but my fear is that I'd have to trade a few internal organs to pay for it. There are a few at f/6.7 or f/6.3 (think, Opteka or Tokina, and mediocre), or there's a couple of pricier f/5 models from Nikon ( Flickr -or- Mir.com) or a Yashica Yashinon DX monster that must be pretty rare. There's a badly reviewed Sigma 500 at f/4, that sounds like a waste, at any price. Non-mirror primes can get a bit faster with more cash to blow, or the Sigma 200-500mm f/2.8 behemoth that will set you back $26K and you'll need a donkey to carry it for you! If one is not financially blessed, then one can make do at f/8, with a little work. The last 5 test shots here are using the so-called Spiratone 'Tomioka' Minitel 500mm (serial #'s of 532xxxx), and were shot on a tripod-mounted Sony A7R, at 1/120 and ISO 200. Keep in mind that it took a good bit of work to make these presentable from a digital setup, and I doubt I'd want to try something similar on film stock. I may end up with a Yashica at some point, or I can always mount a Zeiss 300mm f/4 on my NEX to get a 450mm equivalent FOV. |
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