Macro zoom lens PLUS ext tube for 35mm copy.

[JoolsW]

I've setup my DSLR with macro zoom lens to digitise trannies and negs. I'm very pleased with the results with 120 medium format origials.
BUT, the enlargement isn't enough for 35mm. I've seen the info for calculating size of extension tube /lens size/magnification. But because I'm using a macro lens I'm not sure how that applies.
My 28-105 Nikon lens sets to about 70mm when I do a 120 film. It's a zoom macro. Would I use that 70mm figure to do the sum? or what. I'd need approx 40% more enlargement to get a 35mm to the right size.
Any ideas?
Cheers.

[William Michael]

If this lens is labelled "Macro" I expect it has a feature that you need to engage, for example a lever or switch, to allow it to go to its "Macro" function. I'll answer assuming this as fact. 

I'll re-write your question to ensure I understand it correctly: you're using the lens at FL = 70mm and then you engage the macro function switch and the resultant magnification is suitable for copying your 120 film negatives and transparencies.

You intend using the same lens settings, and you expect you will need about 40% more magnification, to be suitable to copy 135 format film.

Then I believe the answer is - yes, just use "70" as the input for the Focal Length into your calculator.

Rationale - I believe that all the Macro Calculators effect their answer being the increase of the native magnification of the lens in question.

The facts that it is a zoom lens, and that it is labelled "Macro" is irrelevant to your calculation; provided that you contrast/compare the results for the lens when it is at exactly the same settings.

WW         

[JoolsW]

Thanks for your reply William. There is no need at all for me to stick to 70mm FL, my camera stand is adjustable for height. So NO, I don't necessarily need to use the same settings. For previous successful copies from 120 film, I just put the lens on Macro, adjusted the camera height to ballpark then adjusted with the zoom ring, focussed, lifted the mirror and clicked,-Easy.
But with camera height and zoom at max, gives me a 35mm original which fills only about 40% of the camera frame - ie there's too much white space around it.
So I've assumed I need an extension ring to enlarge it further. Problem is I don't know what size extension ring. 
  

[John Seaman]

Instead of spending money on extension tubes I suggest you seriously consider investing in a 1:1 true macro lens.

[JoolsW]

Not worth it, I think I could buy a dedicated 35mm film scanner cheaper.
It must be viable, as my 120 scans are excellent. What's the issue with using an extension tube?

[William Michael]

7 hours ago, JoolsW said:

So I've assumed I need an extension ring to enlarge it further. Problem is I don't know what size extension ring. 

Then I misunderstood that you were seeking a broad response and answered only the specific question, as asked, "Would I use that 70mm figure to do the sum?:"

***

Regarding what size Extension Tube to get (buy), I suggest that you consider buying a set of three.

Whilst Extension Tubes for 135 and APS-C Format Digital cameras are usually available as one size from the host manufacturer, (typically) Tubes come in a set of three from third party manufacturers and there are a few third party sets available for both Nikon and Canon and none are really expensive accessory items.

I am ignorant of the specifics of your particular lens's electronic connection to camera requirements, and you will find that some Extension Tube Sets have electronic connection and some do not - typically those that do have electronic connections are a bit more expensive.

My experience is there are two main issues which might occur with poorer quality tubes:

1. Flare - caused by inferior paint/finish on the inside of the ring (not common but noted in some really cheap offerings)

2. Wobble - caused by the bayonet, end flange  and latching mechanisms being of inferior quality finish and parts 

I use Canon DSLR cameras and whilst Canon make two Extension Tubes (12mm and 25mm) I have had set of Kenko Extension Tubes since I bought into Canon Digital in 2004. My tubes are: 12mm; 20mm and 36mm and they have served me well for 20 years.

One practical value of a set of three tubes, is the range of extension lengths - with the set 12/20/36, one has 12mm; 20mm; 32mm; 36mm; 48mm; 56mm and 68mm extensions available to use.

WW

[William Michael]

 

6 hours ago, JoolsW said:

Not worth it, [considering investing in a 1:1 true macro lens], I think I could buy a dedicated 35mm film scanner cheaper.
It must be viable, as my 120 scans are excellent. What's the issue with using an extension tube?

I think it is wise to consider all options.

I think that there are not big issues with using an extension tube (or using more than one), but other options might have significant advantages now, and/or in the future. 

By definition a 1:1 Macro lens is a viable option for the task of copying 35mm film with a DSLR camera.

Moreover, if you're harvesting a range of options to copy 35mm film, then, I think the better questions to be asking are - "What are the advantages of using a dedicated 1:1 macro lens / or a Film Scanner rather than Extension Tubes?"

I think that a reasonable quality scanner would be quicker, I don't know for sure, but that's a question I would be asking.

Many 1:1 Macro Lenses would offer full dedicated electronic connections to your camera. Quite a few third party Macro Lenses present very good value for money, and good quality.

I reckon it would be worthwhile looking at the offerings from Tokina, Tamron, Sigma (just a sample of some available), and compare the advantages and cost to Extension Tube(s).

I re-iterate that there are quality variants in Extension Tubes - many commentators on the www recite the mantra that Extension Tubes are 'a tube of empty space, buy least expensive tube', I think it a foolish choice to buy any extension tube based solely on price.

WW           

[rodeo_joe1]

Most zoom lenses that claim to be 'macro' are no such thing! True macro-photography starts at 1:1 reproduction ratio - i.e. life-size in the image. 

That out of the way. Yes you can certainly use extension tubes. They usually come in a kit of 3 that gives you multiple magnification options. However I strongly disagree that a true macro lens would be a waste of money. For example: A used 55mm Micro-Nikkor can be got for 60 to 70 UK pounds, and you wouldn't get much of a film scanner for that price, if at all. It will still need an extension tube ( ~ 13mm long) but is capable of much sharper and more detailed digital copies than any zoom lens - 'macro' or otherwise.

You can also find front-of-lens telescoping film holders like this one, if you scour online auctions. 

It makes digital slide/negative copying totally hassle-free. Just point it at a white surface with a flash on the camera.

BTW, this shouldn't be confused with all-in-one slide copier attachments that contain a cheap built-in lens. This one just holds the film or slide in front of a macro lens, and gives the highest quality that the lens is capable of. Grain sharp all across the frame with the right lens like those 55mm Micro-Nikkors - the f/2.8 or f/3.5 versions are just as good as one another for this purpose. 

 

Edited August 22 by rodeo_joe1

[rodeo_joe1]

On 8/19/2024 at 3:33 PM, William Michael said:

I think that a reasonable quality scanner would be quicker, I don't know for sure

Definitely not. Decent film scanners are sloooow. Whereas the device above can copy slides as fast as you can swap them in the holder. Negatives are a different matter; quick to copy but needing inversion in post, and colour correction in the case of colour negs. But even with a film-scanner you rarely get true colour without some manual intervention. 

[ben_hutcherson]

First of all, I think you'd very likely be disappointed with the results of an extension tube on the zoom you've described. Zooms have a lot going on in the optics, and they're often designed to work at their designed distance from the film plane/sensor plane. Without venturing into the weeds too much, I really enjoy doing really high magnification photography(think 2x lifesize, and have pulled off 10x before although I want to redo that particular subject) and find that once I go beyond the lens's designed focus limit, I can usually get much better results using mechanically simpler optics like older unit-focusing micro lenses(think Nikon's 55mm f/3.5) or even enlarger lenses or other short mount lenses. I don't even like the Nikon 55mm f/2.8 AI-s for this sort of job...although at 1/2 life size it's a superb lens and is perfectly acceptable up to 1x.

In any case, I love my scanners, but good scanners are not cheap(even older ones) and as Joe says they are slow. The ones that are cheap are often that way either because they're fairly low quality, have known issues that are likely to disable the scanner, or use obsolete interfaces and some computer know-how(and maybe a secondary hobby in old computers) to get them actually working. Even then, some really high end ones still bring big money.

Nikon's 60mm f/2.8D Micro and 105mm f/2.8D Micro are both relatively inexpensive these days. These can both focus to 1:1 without extension tubes, actually work great as general purpose lenses, and will serve well in this role. The 60mm is probably better for you to dedicate to this role, but IMO the 105mm makes a better general purpose macro lens. Note that they won't autofocus on many DSLRs or any of the Z cameras, but both have very nice manual focus feel and what is to me a nice amount of focus throw(this can be tricky to get right on a macro/micro lens as too little makes precise focusing difficult, and too much feels like you're turning forever to get them in focus). If you're using a full frame camera and copying 35mm negatives/slides, I'd suggest manually focusing to 1:1 and the adjusting the camera distance to get proper focus/framing. In a perfect world, a negative/slide should be in tack-sharp focus with a macro lens set to 1:1 and the negative framed so that it completely fills the frame. If you're using a crop sensor camera, you will need less than 1:1 to fill the frame.