8mm Forum: Zoom and Scope options with Eiki 50mm F1.2

This is topic Zoom and Scope options with Eiki 50mm F1.2 in forum 16mm Forum at 8mm Forum.

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Posted by Akshay Nanjangud (Member # 2828) on August 04, 2013, 07:33 PM:

Hi guys,

I think my Eiki SL-0 is working. Thing is, I will need some zoom and eventually scope too. What is a good combination of lenses to buy with what I already have? I'd like to make a one-time purchase with lenses and just live life. [Smile]

Thanks.

Posted by Maurice Leakey (Member # 916) on August 05, 2013, 10:35 AM:

A zoom converter attachment is cheaper than buying a separate zoom lens.

Posted by Akshay Nanjangud (Member # 2828) on August 05, 2013, 11:21 AM:

What about scope? I already have two lens, then do I need a three lens combination ( one after the other) for scope?

Posted by Martin Jones (Member # 1163) on August 05, 2013, 02:21 PM:

It would help to know what you already have.
I assume you have a projector with just one lens.
What is its focal length (F= XX mm)?
What width and height of picture do you get with it in your CURRENT set-up?
What width and height would you wish to have with a zoom lens fitted?
What is the width of the picture you would want with Scope?

Posted by Akshay Nanjangud (Member # 2828) on August 05, 2013, 02:36 PM:

Current lens: 50mm F1.2
Would like flat prints to be 8' -10' horizontal from a throw of about 15'.
Since I anticipate having more flat prints than scope, the scope dimensions aren't as important.

One question: Is 30mm-70mm lens preferable in smaller homes to the 35-65? I guess the extra 30-35 would help, but not sure.

Posted by Maurice Leakey (Member # 916) on August 05, 2013, 02:51 PM:

For a throw of 15' you will need a 1" (25mm) lens, and this will only give you a picture 5'7" in width. This is a standard 4 x 3 ratio.

An anamorphic in front of the 1" lens will give double the width, i.e., 11'2".

A 30mm will give a slightly larger picture than a 35mm.

Posted by Akshay Nanjangud (Member # 2828) on August 05, 2013, 02:58 PM:

So you are suggesting a 25mm lens for a less than 6' image. Is there a 12.5mm lens for the Eiki projectors? What is the smallest in mm I can get for the Eiki? Do smaller mm lenses reduce sharpness or brightness?

Thanks very much guys.

Posted by Martin Jones (Member # 1163) on August 05, 2013, 03:03 PM:

Using your present lens (50mm) at 15 ft gives you a picture about 2ft 9 in wide.
To get a picture 8 feet wide you would need a lens of about 17 mm focal length.
For 10 ft you would need a lens of about 14 mm focal length.
A 30 -70mm zoom would only enable you to get about 4 ft 7 in at a 15 ft throw.
A 35-65 zoom would only get you about 3ft 11 in at a 15 ft throw.

To achieve your aim at that screen distance, therefore, you would meed to find a lens of around 12.5 mm to 15 mm focal length.

Time for the experts... are there lenses of that focal length to fit Eikis?

Whatever lens you use, adding a Scope lens will double the width. So for a picture 10 ft wide in Scope, you would need a projector lens of 27.5 mm, so a 30-75 zoom would still not give you the width.

Posted by Maurice Leakey (Member # 916) on August 05, 2013, 03:14 PM:

The Elf Instruction Manual states "Additional Lenses" and shows ten lenses, but it does not give sizes; although it does say that the zoom lens attachment is 1.1/2" (38mm) to 2.1/2" (65mm) with the standard prime lens.

The screen size chart only goes down to 1", so I would assume they go no further than 1". If you are lucky to find a 1" lens it will probably cost more than the projector!

Posted by Akshay Nanjangud (Member # 2828) on August 05, 2013, 03:24 PM:

There are 25mm lenses in eBay now for $125. Doesn't seem *too* high to me, but is an investment for sure.

Does sharpness or brightness reduce with reducing mm? Or, is there no relation between these?

Thanks both of you. I am almost getting done. Thanks very much.

Posted by Martin Jones (Member # 1163) on August 05, 2013, 04:21 PM:

The 25mm lens gives you a picture only 5ft 6in wide at 15 ft throw.

And yes, the brightness of the picture with a 25mm is one quarter
of that with the 50mmm since the picture is four times the area.

Posted by Akshay Nanjangud (Member # 2828) on August 05, 2013, 05:02 PM:

Thanks again!

Final question: Does the same zoom converter lens fit both 50mm and 25mm lenses? If yes, then I can effectively go smaller than 25mm.

Posted by Maurice Leakey (Member # 916) on August 05, 2013, 05:10 PM:

The zoom converter screws into the standard 2" lens, but I regret that never having seen an Eiki 1" lens, I cannot answer your question. Is the 1" lens on eBay the following:-

http://www.ebay.com/itm/16MM-LENS-EIKI-ELMO-25MM-LENS-F-1-9-LARGE-PICTURE-IMAGE-/200948989325?pt=US_Film&hash=item2ec97e3d8d

If so, this is not an Eiki lens, it is another lens in an Eiki sleeve. Whereas it will fit your projector, it is highly unlikely that the Eiki zoom adapter will fit to it.

Posted by Akshay Nanjangud (Member # 2828) on August 05, 2013, 06:02 PM:

Maurice, finally you deliver some bad news. [Big Grin]

I am finished! Looks like the lowest I can go is 25mm, and this without zoom. [Frown]

Posted by Maurice Leakey (Member # 916) on August 06, 2013, 12:11 AM:

I assume it is the lens that you mention on eBay, if it is it is quoted as being as f1.9. Your present prime lens is an f1.2, therefore the lens in the sleeve will only pass approximately half the light than the prime lens on your projector.

My advice is not to buy it as at f1.9 it is obviously an old lens. As I said before a proper Eiki lens would cost a lot of money as such wide lens are highly sought-after.

The zoom attachment is a much better idea and should not reduce the prime lens' light output too much. You may have to reconsider your thoughts on the size of picture you want.

http://www.ebay.com/itm/16MM-LENS-ZOOM-CONVERTER-LENS-FOR-EIKI-ELMO-PROJECTORS-0-75-1-25X-/190878479455?pt=US_Film&hash=item2c713e745f

Posted by Akshay Nanjangud (Member # 2828) on August 06, 2013, 01:17 AM:

Maurice, thanks a lot for the advice. It seems my problems are solved. This afternoon a member from another forum offered me an ISCO 35mm-65mm lens at a reasonable price. It appeared to be one of the better options, so I very gratefully accepted the offer.

Posted by Maurice Leakey (Member # 916) on August 06, 2013, 02:11 AM:

Akshay
The ISCO sounds a very useful accessory. Have fun.

Posted by Martin Jones (Member # 1163) on August 06, 2013, 02:35 AM:

I'm puzzled......I quote from my previous post...

"A 35-65 zoom would only get you about 3ft 11 in at a 15 ft throw."

How does that equate to your requirement of 8-10 ft?
It's actually not much better than a 50 mm lens (2ft 9in).

Posted by Akshay Nanjangud (Member # 2828) on August 06, 2013, 03:28 AM:

Martin, you are right. I am aware. It doesn't solve my problem of having an 8' image, I know this. But what are my other options? My choices were:
1. 50mm lens, not good,
2. 25mm lens, good, but no zoom attachment lens came from this thread or other sources, I might still get one of these later.
3. Sankor 30mm-70mm lens, best solution but my sources are all pricey,
4. ISCO 35mm-65mm lens, nice price despite not being the best.
Compromised solution reached. What to do?

I searched this forum and noticed quite a few members are using the ISCO lens. So I too took the plunge.

It is surprising me that my Super 8 set-up will give me an image larger than my 16mm set-up. Any comments?

Posted by Martin Jones (Member # 1163) on August 06, 2013, 04:39 AM:

If I was in your position requiring to fill 8 to 10 ft from 15 ft I would start by acquiring the widest angle lens I could.... the 25mm. This would give me %ft 7in.
I would then need to add an "attachment" to widen this to the required width.
For 8 ft I would need to magnify by 1.4 times, for 10ft by 1.8 times.
There are many "surplus to requirements" Camcorder "wide angle adapters offered regularly on eBay... these widen the angle of view of a Camcorder or other lens; when placed in front of a projector lens they make the picture larger. They are described by their "power", one that enlarges by 2 times is described as X 0.5 (the reciprocal of the magnifying factor).

So for approximately 8ft the power required is X 0.7, for approximately 10 ft the power required is X 0.6.

This one (as an example) http://www.ebay.co.uk/itm/2-x-Japanese-Quality-Camcord er-Conversion-Lenses-0-65x-Wide-Angle-1-5x-Telephoto-/281120617771 would result in a width of about 8ft 8in when used with a 25mm lens at 15ft

The most powerful I have come across is a X 0.5 would give you a picture of 11ft 2in with a 25mm lens , more than you need(or 9 ft 4iin with a 30mm lens).

So, to sum up, I, if personally faced with your problem of getting as wide a picture as possible with such a short throw, would seek the shortest Focal Length lens I could find for the machine (25mm?) and THEN look around for a CHEAR "wide angle adaptor" , of preferably X 0.5 power, to place in front of it.

But I wouldn't compromise with a 35-75 mm Zoom lens as the rest of the "zoom" from 50mm up to 75mm would be pointless in the situation.. it only produces SMALLER pictures! After all, a 25mm and a 50mm set of lenses, with or without a X 0.5 adaptor, is still a very useful set for use on other throws.

EDIT: And here's another.. even more magnification! http://www.ebay.co.uk/itm/52MM-WID EANGLE-TELEPHOTO-LENS-FOR-NIKON-D40-D3000-D5000-/230973601913?pt=UK_Sound_Vision_Other&hash=item35c7197879

Posted by Akshay Nanjangud (Member # 2828) on August 06, 2013, 10:42 AM:

Martin, great stuff! This is indeed what I'd like. Whatever happens, I will definitely get a 25mm lens, as you suggest. I have a doubt: When looking for lenses to fit in front of the 25mm lens, how do I know which lens will fit directly? Is there a specification #?

Posted by Dominique De Bast (Member # 3798) on August 06, 2013, 11:40 AM:

I guess that the reason why the picture is smaller with standard lens on 16 mm is that the makers assumed that a 16 mm projector would often be far away from the screen as this gauge was more "professional" than others. Super 8 was partly promoted on the basis that it could give a larger size than standard 8, so one can think that the projectors makers thought that this what super 8 cusomers wanted.

Posted by Maurice Leakey (Member # 916) on August 06, 2013, 02:27 PM:

In the days before CinemaScope and all the other wide screen processes the standard lens for 35mm cinemas was a 5". On 16mm this equated to a 2".

The reason was the ideal viewing conditions in a certain size auditorium would dictate the best size screen for comfortable viewing.

If anybody contemplates buying a 1" lens for 16mm films and hopes to affix something to get an even bigger picture the final result may not be acceptable for relaxed viewing.

Posted by Akshay Nanjangud (Member # 2828) on August 06, 2013, 02:54 PM:

My hunch was the same as Dominique's.

I will receive the ISCO lens and see how the image is. Later I will also buy the 25mm lens, check that out as well. I just hope my projector lasts that long.

Thanks Martin! Thanks Maurice! I will resurrect this thread after I receive the ISCO lens, which will be around the twentieth of August.

See you all in a fortnight! [Smile]

Posted by Martin Jones (Member # 1163) on August 07, 2013, 04:08 AM:

Akshay,
There is no "specification" common to all lenses for joining purposes. What you will have to do is this...
1. When you have obtained your 25 mm lens, look to see if there io an internal thread on the end facing the screen. If so, try and identify if it is a filter thread size.. 37mm, 42mm, 49mm etc. If there is no thread Measure the OUTSIDE diameter of the lens at that end.
2. Look for an "adaptor lens" that has a "Thread diameter" of at least the previous obtained measurement at the "camera" end, e.g. http://www.ebay.co.uk/itm/52MM-WIDEANGLE-TELEPHOTO-LENS-FOR-NIKON-D40-D3000-D5000-/230973601913?pt=UK_Sound_Vision_Other&hash=item35c7197879 This one is 52mm.

Then find a "step-up" filter ring that will screw onto the adaptor "camera end" and either screw into the front of the projection lens or (if the lens has no internal thread)or just fit snugly over the outside of the lens. If the latter you will either have to fabricate something to hold it firmly or do what I do. I used an epoxy resin to glue the step-up ring onto the lens; the adaptor can be removed or replaced as required and the operation of the main lens is not affected.
Or you can devise your own fixing...
Best of luck. I shall be away for 9 days from later today, out of the reach of computers!
Martin

Posted by Akshay Nanjangud (Member # 2828) on August 08, 2013, 04:53 AM:

Martin, I had ideas similar to what you described. Am not too confident of putting them through. In a week or two I start on a new job that will consume my life. Let us see how much film-time I have from here.

I appreciate your time guys. You have been helpful and I will report back.

Enjoy your nine days away from the forum Martin! [Smile]

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