50mm El_Nikkor vs 40mm Apo-Componon

[NikonUser]

Maple Callus Borer,side view of head (pinned).
IMAGES OF MOTH HERE

El-Nikkor @ 1/2 stop wider than f'/5.6; 74 frames @ 0.01mm; HF stack of RAW
Apo-Componon @ f/2.8; 82 frames @ 0.01mm; HF stack of RAW
Both @ 32.5cm extension; 2 flashes; tried to keep exposure identical.
Frame width 3.5mm = 6.8x mag on sensor
Images cropped to 2500 px (wide) from 4300 px frame; then re-sized to 800px.
Photos taken within 60mins of each other, not sure why eye has more black on one image.

[Cyberspider]

awesome comparison...the contrast of the Nikkor is better but with a editing program you could get equal results!

Is this right? Extension 32,5mm plus 50mmm = 82,5mm
82,5mm:50mm = Magnification: 1,65:1?

[NikonUser]

Hi Markus:
No not 32.5mm but 32.5cm (325mm) (In NA we use a "." rather than a ",").

My camera (D2Xs) will not fit onto the Nikon PB-6 bellows, the base of the camera is too deep. I have to mount an extension tube, a PN11 (52.5mm), between the bellows and the camera. I also have a complex lens mount at the other end of the bellows. Thus with the PN11 + bellows at full extension + lens mount (+ reversed for El Nikkor) I have a total extension of 325mm from the camera/lens mount. Can add another 50mm from the camera/lens mount to the sensor.

To get the same magnification with the 40mm Apo-Componon I needed less extension.

So I should have said the El Nikkor at 32.5cm extension.

The camera's sensor is 23.7mm wide. The image size was 3.5mm. 23.7/3.5 = 6.77x magnification. This is quite a small moth.

The 50mm El Nikkor f/2.8 N is an excellent macro when used in reverse. Bargains are availble on Ebay. Yesterday (7iii09) one sold for $25.00; but I have seen them sell for around $100.00.

PS. In your images "klick" should be "click".

[mgoodm3]

When you crunch the images down to 800 pixels they look very similar. I would be interested in a 100% view of somewhere in there to compare. The resizing may be hiding differences.

That is a high mag for the 50 mm or even the 40 mm. Neither will be anywhere near their best with that much extension.

[NikonUser]

Interesting; what extension (or magnification) do you recommend to get the best image (sharpest, highest resolution) for the 50mm EL-Nikkor f/2.8N?

The booklet that came with the lens gives the "Standard Magnification" for this lens as 8x and the "usable magnification range" 2x - 20x.
This lens was designed for enlarging 36 x 24 mm negatives.

Perhaps the following is false reasoning on my part:
8x mag on a 36mm wide neg = 4.5mm. Thus a 4.5mm wide subject that fills the width of a 36mm sensor will give the best image ??
On a 24mm wide sensor this equates to an image 2/3rds of 4.5 = 3mm.
To get a 3mm subject to fill the width of the 24mm sensor needs >32.5cm extension.

I can re-shoot this subject at what you consider to be the best mag/extension.

[rjlittlefield]

Generally it is best to fill the frame with the subject you care about.

In terms of line pairs per mm (lppm) resolved on subject, the EL-Nikkor will be slightly better at long extension than at short.

The tradeoff is that resolution on subject improves only a little with more extension, while the field of view shrinks a lot. If you look at the resulting full-frame images at same size (not same magnification!), then the lower magnification image will seem sharper. In fact the lower magnification image will be sharper in terms of lppm in the image, though not on the subject.

If your application is such that you care most about a certain size subject but a larger field still has some value, then you'll have to decide which magnification gives you the best tradeoff.

If your application is such that you care only about a certain size subject, then you can safely assume that highest image quality will come from making that subject fill the frame. At that point, the tradeoff becomes which lens and settings to use, for example less resolution with longer working distance or a shorter stack, or more resolution with shorter working distance and a deeper stack.

--Rik

[lothman]

El-Nikkor @ 1/2 stop wider than f'/5.6; 74 frames @ 0.01mm; HF stack of RAW
Apo-Componon @ f/2.8; 82 frames @ 0.01mm; HF stack of RAW
Both @ 32.5cm extension; 2 flashes; tried to keep exposure identical.
Frame width 3.5mm = 6.8x mag on sensor

Amazing pics, but why did you use the Apo wide open and the Nikon stopped down?

Concerning extension, what would be the difference if you use a shorter focal lens and less extension?

Regards
Lothman

[rjlittlefield]

Amazing pics, but why did you use the Apo wide open and the Nikon stopped down?

I'm guessing a little, but HERE, NikonUser says that his Apo-Componon is fixed aperture at f/2.8. If it could be stopped down, it would likely be a little sharper. The EL-Nikkor can be stopped down, and sure enough it gets a little sharper. Most people find the EL-Nikkor 50 mm f/2.8 sharpest between f/4 and f/5.6.

Concerning extension, what would be the difference if you use a shorter focal lens and less extension?

This is an interesting question.

Ignoring lens aberrations, there would be no difference assuming that the effective f-number and magnification were the same.

Considering lens aberrations, the short lens has an advantage. This is because the effect of lens aberrations scales along with the lens focal length.

As a quick review of the theory, you can think of aberrations as being due to slight differences in optical path length for the various ray paths between a single point on the subject and the corresponding point of best focus on the sensor. Suppose those differences are 0.1 wavelength for a particular lens design. If you double the focal length while using the same design, then the whole geometry scales by 2X, and the differences become 0.2 wavelength. Double it again, and the differences become 0.4 wavelength. The effect of 0.1 wavelength is not too bad, but 0.4 wavelength is disastrous. To reach the same 0.1 wavelength differences, the 4X longer lens would have to be more complicated and expensive.

So, given equal cost and within certain limits, there is good reason to expect that a shorter lens will give higher resolution on the subject. This rule of thumb breaks down for very short lenses where angle of view becomes an issue. I have read that very small lens elements are also hard to manufacture, but I don't know how much of an issue this is in practice.

--Rik

[mgoodm3]

I've done a lot of lens testing in the last year and I am kinda manic about image sharpness (maybe to a fault). The way I tend to approach the issue of what to use at what magnification is by the sharpest aperture of the lens vs. magnification. I am going for the best possible image quality here in the way I arrange it. Magnifications for D200 detector. You can push most any lens farther than this but some other lens with a larger aperture will probably do a better job although you will lose DOF.

1:1 to 2:1 : a normal lens with a sharpest aperture of f5.6 or f8 is fine - most short focal length 50 and under will accomplish this.
2:1 to 4:1 : f5.6 and below: I love Oly 38/2.8 at f4 at 2:1 and up, Leica 25/2 at f2.8 at 3:1 and up, reversed Nikon 28/2.8.
4:1 to 8:1 : 4x and above microscope objectives, short focal length bellows lenses - Leica 25/2, macro-nikkor.

I would be happy using a El-nikkor 50/2.8 at 1:1 to 4:1 (I get f5.6 as the sharpest aperture for it)

I don't go much above 8:1 with coins.

[Charles Krebs]

NU,

Take a look at this brochure, specifically the Componon, Componon-S, and Apo Componon HM sections. Note the lenses that are sold in the "BLV-L" mount.

http://www.schneiderkreuznach.com/pdf/f ... rung_e.pdf

That is one of the standard mounts for Schneider enlarging lenses. It has a 43mm front filter size and the Leica thread on the rear.

The 40/2.8 Componon HM in "barrel" that you have can be put into a BLV-L mount. The front and rear components simply unscrew from one barrel and screw into the other.

I unscrewed the front and rear components from a 50/2.8 Componon-S, and put the 40/2.8 HM front and rear components in the BLV-L mount. If desired, it's possible to adjust the aperture blades so that f2.8 is right for the 40mm lens. But it is so close I did not bother. Works just fine.

The reason I did this is that the 40/2.8 Apo Componon HM is very, very good, but I was frustrated because a fixed f2.8 is limiting. The lens really does not seem to get any sharper stopping down, but the image looks a bit better about a half to one stop stop down (contrast picks up). When working at magnifications where large apertures are not needed for diffraction reasons (about 4X and less) it's nice to be able to stop down to 5.6 or so.
My impression is that this lens really excels from about 3X and up.

The term "Apo" can be used rather loosely in photo gear marketing sometimes (just search "Apo" on eBay ) But this is the real deal. As free from chromatic aberration as any lens I've used.

If you keep an eye on eBay you should be able to snag a used lens that has this mount for under $35. (Watch for one with a "haze" or mildew problem on the glass, but with a good barrel). Schneider might let you buy a new empty mount from them, but it would probably cost more.

Charlie

[rjlittlefield]

mgoodm3, just to clarify for other readers...

...but some other lens with a smaller aperture will probably do a better job although you will lose DOF.

"smaller aperture" should be "larger aperture (smaller f-number)", a typo I think.

1:1 to 2:1 : a normal lens with a sharpest aperture of f5.6 or f8 is fine - most short focal length 50 and under will accomplish this.

I'm thinking that "normal" must mean something like an enlarging lens, as opposed to an expensive highly corrected macro lens that works best wide open.

When I started this game, I would have thought "normal lens" meant one from an old 35 mm camera, say 50 mm f/1.8. But those are corrected for distant focus and probably will not do well at 1:1.

--Rik

[mgoodm3]

Fixed the smaller/larger issue.

Normal for me is most anything that is not a specialized bellows lens. Those purpose-built lenses really shine above 2:1

I want to get a 63 macro-nikkor or a 50 mm photar - I suspect that those may shine from 1:1 to 2:1.

[augusthouse]

Did one of our members happen to win the 2.8/40mm APO auction that ended today? If so, well done - spectacular purchase!

An EL-Nikkor 63mm 'N' also went for an exceptionally good price (from a buyer's perspective). In general, they have been selling at low prices for the past four weeks.

Craig

[Charles Krebs]

NU,

Re-read the thread and had a few more thoughts...

The booklet that came with the lens gives the "Standard Magnification" for this lens as 8x and the "usable magnification range" 2x - 20x.
This lens was designed for enlarging 36 x 24 mm negatives.

Perhaps the following is false reasoning on my part:
8x mag on a 36mm wide neg = 4.5mm. Thus a 4.5mm wide subject that fills the width of a 36mm sensor will give the best image ??
On a 24mm wide sensor this equates to an image 2/3rds of 4.5 = 3mm.
To get a 3mm subject to fill the width of the 24mm sensor needs >32.5cm extension.

I think you will find that the amount of extension, in itself, is not a problem (as you mentioned, it was designed to make about an 8x10 inch print from 35mm). The limiting factor for magnification the way we are using it is determined by the effective aperture, which will be determined by the largest aperture at which the lens performs well. A print will not be further enlarged, it is the final product we view. Diffraction is not much of an issue (although you would not want to be making prints at f16 or f11). So an 8x10 inch print made at f5.6 could look tack sharp.

But when used on a 15.7 X 23.7mm sensor the image will need significant enlargement to be of any use. Photographing at 8X, a "marked" f5.6 becomes about f50. Maybe passable for a very small print or web image, but really into serious loss of resolution.

Effective aperture = f (m+1)

The 50/2.8 El Nikkor really should be stopped down at least one stop, and preferably (as you have done here) about a stop and a half.

The Apo Componon HM can, if needed, be used at it's maximum aperture. So it could comfortably be used at a little higher magnification before diffraction becomes too objectionable.

Charlie

[dmillard]

Did one of our members happen to win the 2.8/40mm APO auction that ended today? If so, well done - spectacular purchase!

Craig

Thanks Craig -

That was me. Now I just need to make some time to use it! I like the versatility of Charlie's BLV-L mount idea, but I think I probably will just insert an f/4 Waterhouse stop in the lens because I'm also fond of circular apertures.

David