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Marco
9-Apr-2019, 08:12
Hi everybody!

I'm going to order a 16x20" camera, my intention is to use it in my studio for some portraits with the Harman Positive 16x20".

For my first lens I'm tempted by the Apo Ronar 600mm since I can found it quite cheap in the used market, but I'm wondering if it covers 16x20", I've read that it covers 20x24" with a 1:1 ratio, not sure what that means :( but my idea is that since it is a repro lens the coverage depends on the bellow extension (????), so I think that for my head and shoulder or half body portraits it should be fine, but I am confused, if anyone can help and give me some advice it will be greatly appreciated ;)

Thanks!!!

Pere Casals
9-Apr-2019, 08:38
Datasheet ,

https://onedrive.live.com/?cid=8D71BC33C77D1008&id=8D71BC33C77D1008%21337&parId=8D71BC33C77D1008%21324&o=OneUp

it covers 46, so in theory this is 468mm circle with infinite focus (sin(46/2)*600*2)


Here it says 534mm at 1:10 magnification, I guess this is because of bellows draw to focus near.

https://www.angusparkerphoto.com/blog/2015/2/ulf-lens-recommendations-14x17

Marco
10-Apr-2019, 00:20
Thank you for the reply, the second link helps a lot!

Pere Casals
10-Apr-2019, 03:58
the second link

One of the choices mentioned by Angus Parker is the Symmar 360 convertible to 620. I've one, and I'd like to recommend it. You would have the two focals in shutter. The 620 conversion works pretty well when stopped at f/22, just you need to check focus again after stopping to f/22 because it may have some focus shift.

Many Symmar 360 are in old Compound IV shutters that are simple and reliable, some people destroys those shutters by (brute force) cocking in T or B positions. T and B works without cocking.
http://skgrimes.com/library/used-obsolete-discontinued-shutters/compound

Marco
10-Apr-2019, 05:07
Actually, afternoon reading the article in the link you posted, my attention focused on the Symmar Convertible 360, mainly because I prefer having a shutter, I will use the 16x20" in my studio with the Harman Positive and with strobes, now I'm making portraits with my 8x10" and the Harman and I found a good "compromise" with strobes and 1 second exposure...

Do you know if at 620mm the Symmar covers 16x20" at full aperture?

Thank you again, I really appreciate your help!

Marco

Pere Casals
10-Apr-2019, 06:29
Do you know if at 620mm the Symmar covers 16x20" at full aperture?


It not covers at infinite...

The 620mm conversion has aprox the same circle than the full 360mm lens, this is around 500mm. The 360mm covers 70 at f/16, but 45 for the 620mm rear element alone...

You need 625mm to cover 16x20, so it wil cover for near subjects when you add bellows draw to focus near subjects, if you increase total bellows draw by 110mm to focus then it covers.

It should be investigated if the illumination circle that's larger than coverage would cover the corners. You know, the coverage circle is the inner circle inside the illumination circle that has good optical performance, but for studio portraits you will have OOF background in the corners anyway, so perhaps it can be used.

With the combination of the circle growth from the bellows draw for close subjects, and tolerating soft corners, then it may cover, but this should be tested.

pepeguitarra
10-Apr-2019, 06:38
... I will use the 16x20" in my studio with the Harman Positive and with strobes, now I'm making portraits with my 8x10" and the Harman and I found a good "compromise" with strobes and 1 second exposure...

Marco

I understand you are already using Harman Positive paper in your studio. My question is: Are your customers OK with having their image reversed?

Pere Casals
10-Apr-2019, 09:10
I understand you are already using Harman Positive paper in your studio. My question is: Are your customers OK with having their image reversed?

This is not new, daguerrotypes were also lateraly reversed. This is the price of autenticity. One should compose reversed.

Tin Can
10-Apr-2019, 09:26
Doesn't the reversed portrait more closely resemble a mirror image?

Which is what sitters prefer as that is how they view themselves.

Some are hard to satisfy with reality. A few sitters I make take their own pic, which they pose in a life size monitor in front of them. DSLR of course. With a remote. I just watch...

Marco
10-Apr-2019, 09:43
It not covers at infinite...

The 620mm conversion has aprox the same circle than the full 360mm lens, this is around 500mm. The 360mm covers 70 at f/16, but 45 for the 620mm rear element alone...

You need 625mm to cover 16x20, so it wil cover for near subjects when you add bellows draw to focus near subjects, if you increase total bellows draw by 110mm to focus then it covers.

It should be investigated if the illumination circle that's larger than coverage would cover the corners. You know, the coverage circle is the inner circle inside the illumination circle that has good optical performance, but for studio portraits you will have OOF background in the corners anyway, so perhaps it can be used.

With the combination of the circle growth from the bellows draw for close subjects, and tolerating soft corners, then it may cover, but this should be tested.

Thank you for your very informative reply, you confirmed what I suspected, the ideal will be to test before purchasing, anyway there's a Symmar Convertible on sale on Ebay Italy, the price is right and actually is not an expensive lens, I think I can sell it for the same price in case it doesn't fit my needs, I will have a thought...

Marco
10-Apr-2019, 09:49
I understand you are already using Harman Positive paper in your studio. My question is: Are your customers OK with having their image reversed?

No problem at all, I told them about that and nobody cares, or better, I suggest them not to put on a t shirt or something with some writings, and mainly they follow my advice but some customers don't care about writings too, they are mainly attracted by the fact the the print is unique, the same happens when I do wet collodion portraits...

Pere Casals
10-Apr-2019, 10:23
Doesn't the reversed portrait more closely resemble a mirror image?

Interesting point !

+1

Pere Casals
10-Apr-2019, 10:37
a Symmar Convertible

You mentioned that you are to use strobes... With ancient shutters you may have a problem, sometimes the shutter may not fire the flash. Today's strobes feed a very low voltage to the PC connector and a thin oxide layer in the inner contacts may not allow the signal to pass. In the past a way higher voltage was used and the oxid layer insulation was always broken.

If this happens then a simple interface circuit can be placed in the middle, it will boost the voltage feeding the PC connector, with that solution the firing will never fail.

Vaughn
10-Apr-2019, 17:20
I have a boat-anchor of a Ronar-CL 600/f9. What a beast! Never have used it. The 24" Red Dot Artar has been fine for 8x10 and 11x14 at a fraction of the weight.

All my carbon printed images are reversed...I try to stay away from icons such as Half Dome.

Marco
11-Apr-2019, 03:11
You mentioned that you are to use strobes... With ancient shutters you may have a problem, sometimes the shutter may not fire the flash. Today's strobes feed a very low voltage to the PC connector and a thin oxide layer in the inner contacts may not allow the signal to pass. In the past a way higher voltage was used and the oxid layer insulation was always broken.

If this happens then a simple interface circuit can be placed in the middle, it will boost the voltage feeding the PC connector, with that solution the firing will never fail.

Thank you for pointed that out, yes I definitely use strobes and I have to take into account this aspect too...if I think about image circles and modern shutter the "perfect" lens would be the Fujinon 600C, but they are way toooooo expensive for me...

Anyone has info about the Zeiss Jena Apo Germinar 750mm f/9? I found one for 450 euros...

Tin Can
11-Apr-2019, 06:43
Read this, https://www.arnecroell.com/czj.pdf