Grease options
My experience here is as an ametuer/hobbyist servicing my small number of Nikkor lenses as well as a few lenses for aquaintences etcJapan Hobby Tool #10
An often recommended helicoid grease is Japan Hobby Tool's #10 - the website indicates that the #10 grease has a NLGI 00 consistency, meaing its very light/reqiures low torque to turn. From the JHT materials it is not clear whether consistency listed is worked or unworked penetration measurements.
One common criticism of JHT #10 is that its prone to oil separation from its soap but JHT makes the following directive for use: stir well before use
In my own experience with JHT #10 in its storage container, there was quite a lot of oil that separated (and crept up the threads of its container and out!) and a thin layer sat on top of the soap. However I have heeded advice to only apply a very thin layer to helicoids and so far I've not noticed oil on the internal of the ~10 lenses I've serviced recently. In particular, I don't see any oil seperation in the Nikkor 24mm f/2.8 AI-S I used for comparison described below - this lens was regreased using JHT #10 3-4 months ago and when re-opened everything appears to be in the same place.
It is important to note that even though this grease is light, when over applied to tight threads it also starts to bind making rotation difficult - for such lens helicoid (the Nikkor 105mm f/2.8 AI-S outer and central helicoid comes to mind) a thin/barely visible brush is sufficient and results in the light feel you'd expect from the NGLI #00 grease.
Another option is the Helimax XP grease (NGLI #1) but it's heavier than JHT #10 and its suitablity/experience is as described on various forum and by Kenneth Olsen (below).
(c) Kenneth Olsen (aka mikeno62) - comparison of JHT #10, #30 and Helimax-XP
Other Greases in Europe
For helicoid greases in Europe, alongside various local distributors of JHT (notably Jack Hat in UK), UK based PolarBear Camera supplies some (own brand?) helicoid greases. Unfortunately Kenneth Olsen's limited review of the PolarBear products were not overly impressive, with significant oil separation observed which he feels makes it unsuitable for his lens helicoid needs: in the same review, Olsen makes a similar comment for JHT#10 and says he no longer uses it because of the oil separation (see my comment above about the Nikkor 24mm lens).However, see the instructions from JHT that indicates any grease should be stired before use.
(c) Kenneth Olsen (aka mikeno62) - review of (inexpensive) PolarBear greases
NPC FC-4 / BC-13A
PolarBear also supply a grease called Nippeco NPC BC-13A (equivalent product to FC-4) which they claim to be the same grease as used by Nikon and Canon: Richard Haw also notes that the NPC grease is reportedly used by Nikon, but documentation on the web is scarce but one reference makes the following claim:FC-4 is a grease made by Nippon Koyu, Japan. This is a precision-engineered synthetic grease, used to lubricate one or more of the helicoids, cam tubes and slots, lens keys and sliding areas of tubes in many Nikkor lenses:Interestingly, NPC's website does not reference the FC-4/BC-13A under its specialist product page but a sales contact confirmed they continue to manufacture this grease.
10.5mm fisheye Nikkor JAA62951
14mm F2.8D ED RF Nikkor Ais JAA13051
24mm F2.8D AF Nikkor JAA12551
28mm AF F2.8D Nikkor JAA12851
35-70mm AF F2.8D Zoom Nikkor JAA74351
50mm AF Nikkor f/1.4D AiS JAA01151
50mm AF Nikkor f/1.8 (new) AiS JAA00903
It should be noted that the helicoid pitch and size has an impact on how the same grease feels once applied. This means one application with JHT on one lens with tigher pitch vs looser pitch will feel more dampened/heavy and you should not pack more grease to achieve more resistance, this is where you need a grease with a higher NLGI rating but of course you must use a grease suitable for lens helicoids which means it must not break down in different temperate ranges or over time.
I ordered a unit of the FC-4 equivalent (now produced as Photolub BC-13A) and some comments of experience so far.
- Letting the BC-13A 10mg tin sit after delivery for a few days still showed that there was some very minor oil seperation, with minute amounts of oil sitting on the top of the soap - not as much as in my JHT #10 but 16ml tub which was a distinct layer of oil.
- There is very minor odor from the BC-13A tin when there is none from JHT #10. Unknown whether its the tin or the grease
- The grease when picked up using a brush feels the same consistency as JHt #10
- Based on manufacturer technical specs, it suggests that it NGLI rating would be #00 (the same as JHT #10) given the 401 worked penetration (results in grease being softer) measurement
Japan Hobby Tool #10 vs Stock Nikon
To directly compare JHT #10 to a stock Nikon grease, in particular the one used on the 50mm f/1.8 AI-S, I had serviced a second 50mm f/1.8 AI-S and compared the focus feeling between that and a stock 50mm f/1.8 AI-S: this lens being reported as using BC-13A for its helicoids. The feeling of the focus ring was very close with JHT #10 being a little lighter.NPC FC-4/BC-13A vs Japan Hobby Tool #10
To compare JHT #10 and BC-13A I used the simplest helicoid I currently have access to which was a Nikkor 24mm f/2.8 AI-S main non-CRC helicoid. I had previously applied a non-helicoid specific NLGI #2 lithium grease just to see how it would feel and it was heavy to turn the focus ring. Servicing all the non-CRC helicoids with JHT #10, the focus was smooth and reasonablly light with some dampening as opposed to the very very light feeling of "dry" helicoid (all grease removed and just metal on metal).When comparing BC-13A, I wanted a controlled environment - the outer and central helicoid mating surface cleaned (central and inner helicoid surface not relevant) and the same amount of thin BC-13A grease applied into the helicoid grooves. Reattaching the inner/central/outer helicoid and focus ring, the focus feels a little heavier than JHT #10 but its not stiff, dampening and subjectively feels a little "nicer" but not stiff. The evaluation was made without the optical block so I can feel the focus ring helicoid: When the entire lens is assembled the BC-13A grease contributes to a slightly heavier focus feeling that JHT #10.
This feeling of heavier focus does not correlate to the data sheets' worked penetration vs constiency numbers above but it does suggest that JHT consistency is an unworked measurement.
L: helicoid grease test with lens block removed | R: BC-13A grease applied
Conclusion
Cost in Europe for the 2 greases is high: JHT #10 is ~32 GBP for 15ml whilst FC-4/BC-13A is ~28 GBP for a 10mg tin (annoyingly this is NOT the mass of the grease, but the package weight!) so this is not a cheap item but the Helimax-XP and PolarBear alternatives are almost a 1/2 to a 1/3 of that price.Niche and specialised products are always expensive and sometimes you need to use the tools designed specifically for the job, rather than using some generic lithium grease. In this initial test, both JHT #10 and BC-13A work well and are similar - if you had to choose either one, its very close but they are different consistencies so they have their different appropriate applications. This means, given you don't care for the small difference in grease consistency, the only factor may be the oil separation concern - with only a small sample, I've not seen JHT #10 creep in an actual lens application but this is also over a short observation period: certainyl in storage, JHT #10 shows more separation that BC-13A but storage in relatively larger quanties is not a real world application.
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