Anyone using adapted EF glass in Seafrogs Salted line 8 inch dome?

I am especially interested if anyone has used the Canon EF-s 10-18mm with  a Metabones adapter in the 8 inch dome. I think the adapted 10-18 may be too long, the adapter may also be too wide? Anyway, would appreciate any input on using this lens or any similar lenses.

thanks

Adaptor width should not be a problem; I'm using a Canon EF-S 60mm f/2.8 macro on Metabones IV on a SeaFrogs housing and it fits through the port opening without issues. Lens diameter, specified at 74.6mm, is also okay - the 90mm macro is 79mm wide, and it fits through, if only barely.

Length, however, is another issue - the Sony 10-18mm is 63.5mm long, while Canon 10-18mm is 72mm long, and you need to add the 26mm of difference between E and EF mounts that's made up by the adapter, so you end up with 98mm - about 3.5cm of difference.

In and of itself this is not damning, as the important part is the location of entrance pupil within the lens rather the the location of its front element, and I don't know where exactly the entrance pupil is located in either of these two lenses, but I have a strong suspicion that the Canon 10-18mm will lose some angle of view and corner sharpness versus Sony 10-18mm in this dome purely due to lens positioning. It's better than vignetting, but still not ideal.

Also, keep in mind that while the Salted Line housing ships with zoom gears for Sony 16-50mm and 10-18mm, SeaFrogs do not have a zoom gear for the Canon 10-18mm. Therefore, if you want to have zoom capability on this lens, you will have to design and print your own gear, or adapt one of the SeaFrogs' other gears. The latter task is complicated by the fact that the adapter places the zoom ring on the lens further out into the port, while the zoom knob and its attached beveled gears are mounted inside the housing.

23 minutes ago, Barmaglot said:

Adaptor width should not be a problem; I'm using a Canon EF-S 60mm f/2.8 macro on Metabones IV on a SeaFrogs housing and it fits through the port opening without issues. Lens diameter, specified at 74.6mm, is also okay - the 90mm macro is 79mm wide, and it fits through, if only barely.

Length, however, is another issue - the Sony 10-18mm is 63.5mm long, while Canon 10-18mm is 72mm long, and you need to add the 26mm of difference between E and EF mounts that's made up by the adapter, so you end up with 98mm - about 3.5cm of difference.

In and of itself this is not damning, as the important part is the location of entrance pupil within the lens rather the the location of its front element, and I don't know where exactly the entrance pupil is located in either of these two lenses, but I have a strong suspicion that the Canon 10-18mm will lose some angle of view and corner sharpness versus Sony 10-18mm in this dome purely due to lens positioning. It's better than vignetting, but still not ideal.

Also, keep in mind that while the Salted Line housing ships with zoom gears for Sony 16-50mm and 10-18mm, SeaFrogs do not have a zoom gear for the Canon 10-18mm. Therefore, if you want to have zoom capability on this lens, you will have to design and print your own gear, or adapt one of the SeaFrogs' other gears. The latter task is complicated by the fact that the adapter places the zoom ring on the lens further out into the port, while the zoom knob and its attached beveled gears are mounted inside the housing.

Thank you Barmaglot, once again very helpful! I'm glad that the adapter fits, that's one ticked box at least. My gut feel, from looking at pics of the dome attached is that my 10-18 probably won't fit and if it does, like you say, there will probably compromises in quality that render the size of the dome pointless. I think I will try and convince Seafrogs to sell me the extension port from the port system for the 70-200 f4, that should give the lens the right amount of room I think. I really appreciate your comment!

5 minutes ago, RjbSA said:

I think I will try and convince Seafrogs to sell me the extension port from the port system for the 70-200 f4

This one? It won't fit. Not only is it far too long - eyeballing it, I would estimate about 7-8cm - but it's meant for the A7 series of housings, which use a 90mm diameter port opening, whereas Salted Line housings use an 80mm port. However, a couple months ago I asked them about extension rings, and got this in response:

Quote

we have some extension rings, but an only custom order available. you can contact support@seafrogs.hk, mention your lens and see if we have an extension ring that can be suitable for your lens

So you can get in touch with them and see if they can hook you up with a custom extension for the 8" Salted Line dome that is 3-4cm longer than the standard.

2 minutes ago, Barmaglot said:

This one? It won't fit. Not only is it far too long - eyeballing it, I would estimate about 7-8cm - but it's meant for the A7 series of housings, which use a 90mm diameter port opening, whereas Salted Line housings use an 80mm port. However, a couple months ago I asked them about extension rings, and got this in response:

So you can get in touch with them and see if they can hook you up with a custom extension for the 8" Salted Line dome that is 3-4cm longer than the standard.

https://seafrogs.com.hk/collections/flat-ports/products/flat-long-port-for-a6xxx-series-salted-line-sony-70-200mm-f4-lense

From the above link, I would guess it is the same size as the A7 one so that's disappointing. Will probably have to try another lens.

That one is a complete port, and even if it comes apart into component pieces, there is no guarantee it will fit onto a dome (it uses a different mounting), and it's still far too long.

To be honest, I'm pretty happy with the Sony 10-18mm in the 8" dome. Here are a few full-res, no-crop samples from a recent trip: https://imgur.com/a/31hBP1U - the corners could be better, perhaps in a Nauticam housing with a properly tuned port, but I'm not willing to make that kind of investment for a relatively minimal gain.

7 minutes ago, Barmaglot said:

That one is a complete port, and even if it comes apart into component pieces, there is no guarantee it will fit onto a dome (it uses a different mounting), and it's still far too long.

To be honest, I'm pretty happy with the Sony 10-18mm in the 8" dome. Here are a few full-res, no-crop samples from a recent trip: https://imgur.com/a/31hBP1U - the corners could be better, perhaps in a Nauticam housing with a properly tuned port, but I'm not willing to make that kind of investment for a relatively minimal gain.

 

Those are some stunning pics! That first fan one is lovely. Really nice clean corners as well. Thanks for the samples, cool to see some good results.

@Barmaglot I've got one last question if you don't mind, If you have the Seafrogs long macro port (I'm just assuming 'cause you mentioned the 90mm macro), which of the two ports (long macro and 8 inch dome) is taller/longer from mount to end if placed mount down on a surface. If the long macro is taller, is it by a lot?

Short macro port, long macro port, 8-inch dome:

By the way, if you're looking to adapt Canon EF glass to a Sony, you may want to take a look at a Tokina 10-17mm fisheye rather than the Canon 10-18mm. Over at Scubaboard, Lewis88 has developed a zoom ring to use it with a SeaFrogs housing (link).

Exactly what I needed! I'd really like to stick to my lens but the tokina is a nice alternative if the former doesn't work out. Thanks, I owe you big time for all the help.

12 hours ago, Barmaglot said:

That one is a complete port, and even if it comes apart into component pieces, there is no guarantee it will fit onto a dome (it uses a different mounting), and it's still far too long.

To be honest, I'm pretty happy with the Sony 10-18mm in the 8" dome. Here are a few full-res, no-crop samples from a recent trip: https://imgur.com/a/31hBP1U - the corners could be better, perhaps in a Nauticam housing with a properly tuned port, but I'm not willing to make that kind of investment for a relatively minimal gain.

 

What type of aperture(s) are those shot with?

Thanks,

- brett

7 hours ago, RjbSA said:

Exactly what I needed! I'd really like to stick to my lens but the tokina is a nice alternative if the former doesn't work out. Thanks, I owe you big time for all the help.

I'm not sure what you're trying to do with this, but keep in mind that internally, the long macro port is a very close fit for the 90mm lens, so you can use the SEL90M28G dimensions as a guideline.

10 minutes ago, TmxDiver said:

What type of aperture(s) are those shot with?

f/11, f/11, f/11, f/11, f/14, f/8.

Just wanted an estimate of size. I’ve gone ahead and ordered a housing and the dome so will find out soon.